Fixed abrasive finishing element having aids finishing method

ABSTRACT

A method of using a finishing element having a fixed abrasive finishing surface including boundary lubricants for finishing semiconductor wafers is described. The lubricants in the finishing element are transferred to operative finishing interface a forming lubricating boundary layer. The lubricating boundary layer thickness is controlled to improve finishing and reduce unwanted surface defects. Differential lubricating boundary layer methods are described to differentially finish semiconductor wafers. Planarization and localized finishing can be improved using differential lubricating boundary layer methods of finishing.

This application claims the benefit of Provisional Application Ser. No.60/107,301 filed on Nov. 6, 1998 entitled “Method of finishing with afixed abrasive finishing element having finishing aids”; and ProvisionalApplication Ser. No. 60/111,969 filed on Feb. 6, 1999 entitled“Finishing semiconductor wafers with a multi-layer fixed abrasivefinishing element having finishing aids”. Provisional Applications whichthis application claims benefit to are included herein by reference intheir entirety.

BACKGROUND ART

Chemical mechanical polishing (CMP) is generally known in the art. Forexample U.S. Pat. No. 5,177,908 to Tuttle issued in 1993 describes afinishing element for semiconductor wafers, having a face shaped toprovide a constant, or nearly constant, surface contact rate to aworkpiece such as a semiconductor wafer in order to effect improvedplanarity of the workpiece. U.S. Pat. No. 5,234,867 to Schultz et. al.issued in 1993 describes an apparatus for planarizing semiconductorwafers which in a preferred form includes a rotatable platen forpolishing a surface of the semiconductor wafer and a motor for rotatingthe platen and a non-circular pad is mounted atop the platen to engageand polish the surface of the semiconductor wafer. Fixed abrasivefinishing elements are known for polishing semiconductor layers. Anexample is WO 98/18159 PCT application by Minnesota Mining andManufacturing.

An objective of polishing of semiconductor layers is to make thesemiconductor layers as nearly perfect as possible. Fixed abrasivefinishing pad finishing surfaces can suffer from being overly harsh on aworkpiece causing unwanted scratching or other unwanted surface damagethus reducing the perfection of the surface. Further, a fixed abrasivefinishing pad finishing surface can suffer from having a higher thannecessary friction when finishing a workpiece. This higher thannecessary friction can lead to other unwanted surface damage. Further,fixed abrasive finishing pads can have abrasive particles unexpectedlybreak away from their surface during finishing and these broken awayabrasive particles can scratch or damage the workpiece surface. Stillfurther, during finishing a particle can break away from the workpiecesurface forming a workpiece abrasive particle which can scratch ordamage the workpiece surface. These unwanted effects are particularlyimportant and deleterious to yield when manufacturing electronic waferswhich require extremely close tolerances in required planarity andfeature sizes.

It is an advantage of this invention to reduce the harshness of fixedabrasive finishing pads on the workpiece surface being finished. It isan advantage of this invention to reduce unwanted scratching or otherunwanted surface damage on the workpiece surface during finishing. It isfurther an advantage of this invention to reduce the friction duringfinishing to help reduce unwanted surface damage. It is an advantage ofthis invention to reduce unwanted damage to the workpiece surface whenduring finishing with a fixed abrasive finishing element an abrasiveparticle unexpectedly breaks away from their surface. It is an advantageof the invention to reduce unwanted damage to the workpiece surface whenan abrasive workpiece particle breaks away workpiece surface duringfinishing. It is further an advantage of this invention to help improveyield for workpieces having extremely close tolerances such assemiconductor wafers.

These and other advantages of the invention will become readily apparentto those of ordinary skill in the art after reading the followingdisclosure of the invention.

BRIEF DESCRIPTION OF DRAWING FIGURES

FIG. 1 is an artist's drawing of the interrelationships of the differentmaterials when finishing according to this invention.

FIG. 2 is an artist's drawing of a particularly preferred embodiment ofthis invention including the interrelationships of the different objectswhen finishing according to this invention.

FIG. 3 is an closeup drawing of a preferred embodiment of this invention

FIG. 4 is cross-sectional view of a fixed abrasive finishing element

FIG. 5 is an artist's representation of finishing some unwanted raisedregions and some regions below the unwanted raised regions withdifferential boundary lubrication.

FIG. 6 is an artist's representation of an example of the effects on theboundary layer lubrication.

REFERENCE NUMERALS IN DRAWINGS

Reference Numeral 4 direction of rotation of the finishing elementfinishing surface

Reference Numeral 6 direction of rotation of the workpiece beingfinished

Reference Numeral 8 center of the rotation of the workpiece

Reference Numeral 10 finishing composition feed line for addingfinishing chemicals

Reference Numeral 12 reservoir of finishing composition

Reference Numeral 14 alternate finishing composition feed line foradding alternate finishing chemicals

Reference Numeral 16 a reservoir of alternate finishing composition

Reference Numeral 16 rotating carrier for the workpiece

Reference Numeral 18 operative contact element

Reference Numeral 20 workpiece

Reference Numeral 21 workpiece surface facing away from the workpiecesurface being finished.

Reference Numeral 22 surface of the workpiece being finished

Reference Numeral 23 raised surface perturbation

Reference Numeral 24 finishing element

Reference Numeral 25 fixed abrasive particles proximate the finishingelement finishing surface.

Reference Numeral 26 finishing element finishing surface

Reference Numeral 27 finishing aid in the form of discrete regions

Reference Numeral 28 finishing element surface facing away fromworkpiece surface being finished

Reference Numeral 29 finishing element surface layer

Reference Numeral 30 finishing element subsurface layer

Reference Numeral 31 finishing composition

Reference Numeral 32 operative finishing motion

Reference Numeral 33 pressure applied to the operative finishinginterface substantially perpendicular to the finishing motion

Reference Numeral 40 platen

Reference Numeral 42 surface of the platen facing the finishing element

Reference Numeral 44 surface of the platen facing away from thefinishing element

Reference Numeral 54 base support structure

Reference Numeral 56 surface of the base support structure facing theplaten

Reference Numeral 60 carrier housing

Reference Numeral 62 pressure distributive element

Reference Numeral 800 portion of a semiconductor wafer surface havingtwo unwanted raised regions.

Reference Numeral 802 unwanted raised regions on the semiconductorsurface being finished.

Reference Numeral 804 lower local regions on the semiconductor surfacebeing finished proximate to the unwanted raised regions.

Reference Numeral 810 finishing surface contacting unwanted raisedregions

Reference Numeral 812 finishing element surface local region displacedfrom but proximate to and lower than the unwanted raised local regions.

Reference Numeral 900 boundary layer lubrication.

Reference Numeral 902 thinner regions of boundary layer lubrication

Reference Numeral 904 thicker regions of boundary layer lubrication

SUMMARY OF INVENTION

A preferred embodiment of this invention is directed to a method offinishing of a semiconductor wafer surface being finished comprising thestep of providing a finishing element having a fixed abrasive finishingsurface and having a organic boundary lubricant therein which is free ofencapsulating films; the step of positioning the semiconductor wafersurface being finished proximate to the finishing surface; the step ofapplying an operative finishing motion in the operative finishinginterface; and wherein applying the operative finishing motion transfersthe organic boundary lubricant from the finishing surface to theoperative finishing interface in a manner that forms an organiclubricating boundary layer of from 1 to 6 molecules thick.

Other preferred embodiments of my invention are described herein.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The book Chemical Mechanical Planarization of Microelectric Materials bySteigerwald, J. M. et al published by John Wiley & Sons, ISBN 0471138274generally describes chemical mechanical finishing and is included hereinby reference in its entirety for general background. In chemicalmechanical finishing the workpiece is generally separated from thefinishing element by a polishing slurry. The workpiece surface beingfinished is in parallel motion with finishing element finishing surfacedisposed towards the workpiece surface being finished. The abrasiveparticles such as found in a polishing slurry interposed between thesesurfaces finish the workpiece.

Discussion of some of the terms useful to aid in understanding thisinvention are now presented. Finishing is a term used herein for bothplanarizing and polishing. Planarizing is the process of making asurface which has raised surface perturbations or cupped lower areasinto a planar surface and thus involves reducing or eliminating theraised surface perturbations and cupped lower areas. Planarizing changesthe topography of the work piece from non planar to ideally perfectlyplanar. Polishing is the process of smoothing or polishing the surfaceof an object and tends to follow the topography of the workpiece surfacebeing polished. A finishing element is a term used herein to describe apad or element for both polishing and planarizing. A finishing elementfinishing surface is a term used herein for a finishing element surfaceused for both polishing and planarizing. A finishing element planarizingsurface is a term used herein for a finishing element surface used forplanarizing. A finishing element polishing surface is a term used hereinfor a finishing element surface used for polishing. Workpiece surfacebeing finished is a term used herein for a workpiece surface undergoingeither or both polishing and planarizing. A workpiece surface beingplanarized is a workpiece surface undergoing planarizing. A workpiecesurface being polished is a workpiece surface undergoing polishing. Thefinishing cycle time is the elapsed time in minutes that the workpieceis being finished. A portion of a finishing cycle time is about 5% to95% of the total finishing cycle time in minutes and a more preferredportion of a finishing cycle time is 10% to 90% of the total finishingcycle time in minutes. The planarizing cycle time is the elapsed time inminutes that the workpiece is being planarized. The polishing cycle timeis the elapsed time in minutes that the workpiece is being polishing.FIGS. 1-3 are now discussed to better illustrate the invention.

As used herein, an emulsion is a fluid containing a microscopicallyheterogeneous mixture of two (2) normally immiscible liquid phases, inwhich one liquid forms minute droplets suspended in the other liquid. Asused herein, a surfactant is a surface active substance, i. e., alters(usually reduces) the surface tension of water. Non limiting examples ofsurfactants include ionic, nonionic, and cationic. As used herein, alubricant is an agent that reduces friction between moving surfaces. Ahydrocarbon oil is a non limiting example. As used herein, soluble meanscapable of mixing with a liquid (dissolving) to form a homogeneousmixture (solution).

As used herein, a dispersion is a fluid containing a microscopicallyheterogeneous mixture of solid phase material dispersed in a liquid andin which the solid phase material is in minute particles suspended inthe liquid. As used herein, a surfactant is a surface active substance,i. e., alters (usually reduces) the surface tension of water. Nonlimiting examples of surfactants include ionic, nonionic, and cationic.As used herein, a lubricant is an agent that reduces friction betweenmoving surfaces. As used herein, soluble means capable of mixing with aliquid (dissolving) to form a homogeneous mixture (solution).

As used herein, a die is one unit on a semiconductor wafer generallyseparated by scribe lines. After the semiconductor wafer fabricationsteps are completed, the die are separated into units generally bysawing. The separated units are generally referred to as “chips”. Eachsemiconductor wafer generally has many die which are generallyrectangular. The terminology semiconductor wafer and die are generallyknown to those skilled in the arts. As used herein, within dieuniformity refers to the uniformity of within the die. As used herein,local planarity refers to die planarity unless specifically definedotherwise. Within wafer uniformity refers to the uniformity of finishingof the wafer. As used herein, wafer planarity refers to planarity acrossa wafer. Multiple die planarity is the planarity across a defined numberof die. As used herein, global wafer planarity refers to planarityacross the entire semiconductor wafer planarity. Planarity is importantfor the photolithography step generally common to semiconductor waferprocessing, particularly where feature sizes are less than 0.25 microns.As used herein, a device is a discrete circuit such as a transistor,resistor, or capacitor. As used herein, pattern density is ratio of theraised (up) area in square millimeters to the to area in squaremillimeters of region on a specific region such as a die orsemiconductor wafer. As used herein, pattern density is ratio of theraised (up) area in square millimeters to the total area in squaremillimeters of region on a specific region such as a die orsemiconductor wafer. As used herein, line pattern density is the ratioof the line width to the pitch. As used herein, pitch is line width plusthe oxide space. As an illustrative example, pitch is the copper linewidth plus the oxide spacing. Oxide pattern density, as used herein, isthe volume fraction of the oxide within an infinitesimally thin surfaceof the die.

FIG. 1 is an artist's drawing of a particularly preferred embodiment ofthis invention when looking from a top down perspective including theinterrelationships of some important objects when finishing according tothe method of this invention. Reference Numeral 24 represents theabrasive finishing element. Reference Numeral 26 represents the abrasivefinishing element finishing surface. Reference Numeral 4 represents thedirection of rotation of the finishing element finishing surface.Reference Numeral 20 represents the workpiece being finished. Theworkpiece surface facing the finishing element finishing surface is theworkpiece surface being finished. Reference Numeral 6 represents thedirection of rotation of the workpiece being finished. Reference Numeral8 is the center of the rotation of the workpiece. Reference Numeral 10represents a finishing composition feed line for adding other chemicalsto the surface of the workpiece such as acids, bases, buffers, otherchemical reagents, and the like. The finishing composition feed line canhave a plurality of exit orifices. Reference Numeral 12 represents areservoir of finishing composition to be fed to finishing elementfinishing surface. Not shown is the feed mechanism for the finishingcomposition such as a variable pressure or a pump mechanism. Supplying afinishing composition without abrasives is preferred and supplying afinishing composition without abrasive particles is more preferred forsome applications such as where a fixed abrasive finishing elementfinishing surface is used for finishing. Supplying a lubricant which isfree of an encapsulating film or encapsulating thin resin structure ispreferred. Encapsulating lubricants is an expensive and complex stepwhich is unnecessary in this invention. Further, encapsulated lubricantstend to burst on breaking and can deliver higher than desired localizedlubricants to regions. Further, the encapsulated lubricants canprematurely burst releasing their contents during manufacture of theslurry and/or finishing element. This can contaminate the slurry and/orfinishing element and adversely affect their respective finishingperformance. Reference Numeral 14 represents an alternate finishingcomposition feed line for adding a finishing chemicals composition tothe finishing element finishing surface to improve the quality offinishing. Reference Numeral 16 represents an alternate finishingcomposition reservoir of chemicals to be, optionally, fed to finishingelement finishing surface. Not shown is the feed mechanism for thealternate finishing composition such as a variable pressure or a pumpmechanism. A preferred embodiment of this invention is to feed liquidsfrom the finishing composition line and the alternate finishingcomposition feed line which are free of abrasive particles. Anotherpreferred embodiment, not shown, is to have a wiping element, preferablyan elastomeric wiping element, to uniformly distribute the finishingcomposition(s) across the finishing element finishing surface.Nonlimiting examples of some preferred dispensing systems and wipingelements is found in U.S. Pat. No. 5,709,593 to Guthrie et. al., U.S.Pat. No. 5,246,525 to Junichi, and U.S. Pat. No. 5,478,435 to Murphy et.al. and are included herein by reference in their entirety for generalguidance and appropriate modifications by those generally skilled in theart for supplying lubricating aids. Reference Numeral 500 represents aoperative sensor. An energy change sensor is a preferred operativesensor. Reference numeral 510 represents a processor. Reference Numeral520 represents a controller. Reference Numeral 530 represents theoperative connections for controlling. Illustrative preferred examplesinclude controlling the operative finishing motion. Further examples arediscussed herein below. FIGS. 2 and 3 will now provide an artists'expanded view of some relationships between the workpiece and the fixedabrasive finishing element.

FIG. 2 is an artist's closeup drawing of the interrelationships of someof the important aspects when finishing according to a preferredembodiment of this invention. Reference Numeral 20 represents theworkpiece. Reference Numeral 21 represents the workpiece surface facingaway from the workpiece surface being finished. Reference Numeral 22represents the surface of the workpiece being finished. ReferenceNumeral 23 represents a high region (unwanted raised region) on theworkpiece surface being finished. During finishing, the high region ispreferably substantially removed and more preferably, the high region isremoved and surface polished. Reference Numeral 24 represents theabrasive finishing element having a finishing aid contained therein. Afixed abrasive finishing element having a finishing aid comprising apolymeric lubricating aid at least partially dispersed therein isparticularly preferred. Reference Numeral 26 represents the surface ofthe finishing element facing the workpiece and is often referred toherein as the finishing element finishing surface. An abrasive finishingsurface is a preferred finishing element finishing surface and a fixedabrasive finishing surface is a more preferred finishing elementfinishing surface. Reference Numeral 30 represents a finishingcomposition and optionally, the alternate finishing composition disposedbetween the workpiece surface being finished and finishing elementfinishing surface. The interface between the workpiece surface beingfinished and the finishing element finishing surface is often referredto herein as the operative finishing interface. A finishing compositioncomprising a water based composition is preferred. A finishingcomposition comprising an water based composition which is substantiallyfree of abrasive particles is preferred. The workpiece surface beingfinished is in operative finishing motion relative to the finishingelement finishing surface. The workpiece surface being finished inoperative finishing motion relative to the finishing element finishingsurface is an example of a preferred operative finishing motion.Reference Numeral 32 represents a preferred operative finishing motionbetween the surface of the workpiece being finished and finishingelement finishing surface. Reference Numeral 33 represents a pressureapplied to the operative interface perpendicular to operative finishingmotion.

FIG. 3 is an artist's closeup drawing of a preferred embodiment of thisinvention showing some further interrelationships of the differentobjects when finishing according to the method of this invention.Reference Numeral 16 represents a carrier for the workpiece and in thisparticular embodiment, the carrier is a rotating carrier. The rotatingcarrier is operable to rotate the workpiece against the finishingelement which rests against the platen and optionally has a motor.Optionally, the rotating carrier can also be designed to move theworkpiece laterally, in an arch, figure eight, or orbitally to enhanceuniformity of polishing. The workpiece is in operative contact with therotating carrier and optionally, has an operative contact element(Reference Numeral 18) to effect the operative contact. An illustrativeexample of an operative contact element is a workpiece held in place tothe rotating carrier with a bonding agent (Reference Numeral 18). A hotwax is an illustrative example of a preferred bonding agent.Alternately, a porometric film can be placed in the rotating carrierhaving a recess for holding the workpiece. A wetted porometric film(Reference Numeral 18) will hold the workpiece in place by surfacetension. An adherent thin film is another preferred example of placingthe workpiece in operative contact with the rotating carrier. ReferenceNumeral 20 represents the workpiece. Reference Numeral 21 represents theworkpiece surface facing away from the workpiece surface being finished.Reference Numeral 22 represents the surface of the workpiece beingfinished. Reference Numeral 24 represents the finishing element.Reference Numeral 26 represents the finishing element finishing surface.Reference Numeral 28 represents the surface of the finishing elementfacing away from the workpiece surface being finished. Reference Numeral31 represents the finishing composition and optionally, the alternatefinishing composition supplied between the workpiece surface beingfinished and surface of the finishing element facing the workpiece. Forsome applications the finishing composition and the alternate finishingcomposition can be combined into one feed stream, preferably free ofabrasive particles. Reference Numeral 32 represents a preferreddirection of the operative finishing motion between the surface of theworkpiece being finished and the finishing element finishing surface.Reference Numeral 40 represents the platen or support for the finishingelement. The platen can also have an operative finishing motion relativeto the workpiece surface being finished. Reference Numeral 42 representsthe surface of the platen facing the finishing element. The surface ofthe platen facing the finishing element is in support contact with thefinishing element surface facing away from the workpiece surface beingfinished. The finishing element surface facing the platen can,optionally, be connected to the platen by adhesion. Frictional forcesbetween the finishing element and the platen can also retain thefinishing element against the platen. Reference Numeral 44 is thesurface of the platen facing away from the finishing element. ReferenceNumeral 54 represents the base support structure. Reference Numeral 56represents the surface of the base support structure facing the platen.The rotatable carrier (Reference Number 16) can be operatively connectedto the base structure to permit improved control of pressure applicationat the workpiece surface being finished (Reference Numeral 22).

A fixed abrasive finishing element finishing surface tends to have ahigher friction than necessary with the workpiece being finished. Thehigher friction can lead to higher than necessary energy for finishing.The higher friction can lead to destructive surface forces on theworkpiece surface which cause deleterious surface damage to theworkpiece. The higher friction can lead to premature wear on thefinishing element and the abrasive particles themselves. This prematurewear on the finishing element and abrasive particles themselves canunnecessarily increase the cost of finishing a workpiece. Forming anorganic lubricating boundary layer is a preferred method to reduce thewear on the exposed fixed abrasive finishing surface during finishing.The this higher than necessary friction can lead to higher thannecessary changes in performance of the finishing element finishingsurface during the finishing of a plurality of workpieces which makesprocess control more difficult and/or complex. Applicant currentlybelieves that the higher than desirable defects in the workpiece surfacebeing finished can at least partially due to the fact that the abrasiveparticles in a previous fixed abrasive finishing elements tend toscratch or gouge the surface because they are not free to move ascompared to abrasive particles in a fluid slurry which are free to rolland move during finishing. Further, since the fixed abrasive finishingelement has fixed abrasive particles in a constant relative positionversus the workpiece surface being finished, applicant believes it iseasier for finishing surface of the abrasive particles to become dull orless effective at finishing the workpiece surface being finished whencompared to abrasive particles in a slurry. Each of the above situationscan lead to less than desirable surface quality on the workpiece surfacebeing finished and earlier than necessary wear on the expensive fixedabrasive finishing element finishing surface. Applicant currentlybelieves that proper choice of a finishing aid, more preferably alubricating aid, at or proximate the surface of the finishing elementfinishing surface can reduce or eliminate the high tendency to scratchand/or damage workpiece surface being finished. Applicant currentlybelieves that proper choice and supply of a finishing aid, morepreferably a lubricating aid, from the finishing element to theinterface of the workpiece surface being finished and the finishingelement finishing surface can reduce or eliminate the negative effectsof high friction such as chatter. Applicant currently believes thatproper choice and supply of a finishing aid to the interface of theworkpiece surface being finished and the finishing element finishingsurface can extend the useful life of the finishing element finishingsurface by reducing erosive and other wear forces. A finishing aid, morepreferably a lubricating aid, reduces the wear to the tips of theabrasive particles due to attrition wear and tribochemical wear. Thusthe lubricating aid can help to maintain the “cutting ability” of theabrasive particles. Supplying the lubricating aid at the point of usefrom the finishing element finishing surface can reduce or preventnegative interactions between the finishing composition and anylubricating aid which might be added to the finishing composition (andoptional slurry particles therein). Supplying the lubricating aid fromthe finishing element finishing surface can further reduce the ofchatter, micro localized distortions in the finishing element finishingsurface, and also increases the uniformity of finishing across thesurface of the workpiece surface being finished. Preferably thelubricating aid is dispersed proximate the finishing element finishingsurface and more preferably, the lubricating aid is dispersedsubstantially uniformly proximate the finishing element finishingsurface. Supplying an organic boundary lubricant to the operativefinishing interface (located between finishing element finishing surfaceand the workpiece surface being finished) further reduces risks ofchatter, micro localized distortions in the finishing element finishingsurface, and also increases the uniformity of finishing across thesurface of the workpiece surface being finished. Forming the lubricatingboundary layer differentially can improve local planarity and enhancefinishing flexibility as discussed herein. Lubrication reduces abrasivewear to the abrasive particles and to the finishing element finishingsurface by reducing friction forces. Differential boundary lubricationcan enhance localized finishing rates to improve the semiconductor wafersurface. Lubrication reduces breaking away of the abrasive particlesfrom the surface of the fixed abrasive finishing element by reducingfriction forces. Lubrication reduces the friction which can reduceadverse forces particularly on a high speed belt fixed abrasivefinishing element which under high friction can cause belt chatter,localized belt stretching, and/or belt distortions, high tendency toscratch and/or damage workpiece surface being finished. Localized and ormicro localized distortions to the surface of a fixed abrasive finishingelement and chatter can also occur with other finishing motionsand/elements and lubrication can reduce or eliminate these.

Supplying of finishing aid from the finishing element finishing surfaceto the interface of the workpiece surface being finished and thefinishing element finishing surface to extend the finishing elementfinishing surface useful life is preferred. Supplying of finishing aidfrom the finishing element finishing surface to the interface of theworkpiece surface being finished and the finishing element finishingsurface to reduce unwanted surface defects in the workpiece surfacebeing finished is preferred. Supplying of finishing aid from thefinishing element finishing surface to the interface of the workpiecesurface being finished and the finishing element finishing surface toreduce unwanted breaking away of abrasive particles from the fixedabrasive finishing element finishing surface is preferred. Supply oflubricant at the point of use is preferred and supply of lubricant witha substantially uniform way to the operative finishing interface at thepoint of use is currently more preferred. An effective amount offinishing aid from the finishing element finishing surface often canhelp meeting a plurality of these objectives simultaneously. Supply of athin lubricating boundary layer is particularly preferred. An effectiveamount of boundary lubricant often can help meeting a plurality of theseadvantages simultaneously.

The new problem recognition and unique solution are new and consideredpart of this current invention.

Fixed abrasive finishing element

FIG. 4 represents an artist's cross-sectional view of a preferredembodiment of a multi-layer fixed abrasive finishing element accordingto this invention. Reference Numeral 24 represents the finishing elementfinishing surface layer. Reference Numeral 26 represents the finishingelement finishing surface. Reference Numeral 28 represents the surfaceof the finishing element surface layer facing away from the workpiecesurface being finished. Reference Numeral 25 represents the fixedabrasive particles proximate the finishing element finishing surface.Preferably the fixed abrasive particles are dispersed in the finishingelement finishing surface layer and more preferably, the fixed abrasiveparticles are uniformly dispersed in the finishing element finishingsurface layer. Reference Numeral 27 represents the finishing aid whichin this embodiment is shown in the form of discrete regions in thefinishing element finishing surface layer. A finishing element finishingsurface layer having finishing aids dispersed in the finishing elementfinishing surface layer is preferred and a finishing element finishingsurface layer having finishing aids uniformly dispersed in the finishingelement finishing surface layer is more preferred. A finishing aidmolecularly dispersed in the finishing element is a preferred type ofdispersion. A finishing aid having a plurality of discrete regions inthe finishing element finishing surface layer is a particularlypreferred form of dispersion and a finishing aid having disperseddiscrete, unconnected finishing aid particles therein is a moreparticularly preferred form of dispersion in the finishing elementfinishing surface layer. Reference Numeral 29 represents a finishingelement finishing surface layer. Reference numeral 30 represents afinishing element subsurface layer. A particularly preferred finishingelement subsurface layer is free of lubricant. A finishing elementsubsurface layer free of lubricant is often a lower cost preferredreinforcement layer for the finishing element. A finishing elementsurface layer and a finishing element subsurface layer comprising ansynthetic organic polymer is preferred. A finishing element finishingsurface comprising binder resin is also preferred. A preferred optionalstabilizing filler dispersed in the finishing element surface layer isnot shown in this particular embodiment. A preferred stabilizing filleris a fibrous filler. An optional reinforcing layer is not shown in thisparticular embodiment. A preferred finishing element subsurface layeruseful for a reinforcing layer can be a synthetic resin fabric, a wovenfabric, a reinforcing film, or reinforcing sheet integral with or bondedto the finishing element body.

A finishing element having fixed abrasives for finishing high precisionworkpieces is known. As used herein, a fixed abrasive finishing elementis a integral abrasive finishing element. The integral abrasivefinishing element having abrasive particles connected to at least thesurface of the finishing element finishing surface layer is preferred.The integral abrasive finishing element surface layer having abrasiveparticles connected to at least the surface of the finishing element andwhich is substantially free of unconnected abrasive particles except forthose formed during the actual planarizing and/or polishing processitself is more preferred. A three dimensional fixed abrasive finishingelement surface layer as used herein is a fixed abrasive finishingelement surface layer having multiple abrasive particles dispersedthroughout at least a portion of its thickness, such that if some of thesurface is removed additional abrasive particles are exposed on thenewly exposed surface. A three dimensional fixed abrasive finishingelement surface layer is particularly preferred. A three dimensionalfixed abrasive finishing element surface layer having multiple abrasiveparticles substantially uniformly dispersed throughout at least aportion of its thickness such that if some of the surface is removedanother region of substantially uniformly dispersed abrasive particlesare exposed on the newly exposed surface is preferred. A threedimensional fixed abrasive finishing element surface layer havingmultiple abrasive particles uniformly dispersed throughout at least asportion of its thickness such that if some of the surface is removedanother region of uniformly dispersed abrasive particles are exposed onthe newly exposed surface is more preferred. A fixed abrasive finishingelement surface layer which applies a substantially uniform distributionof abrasive particles over the workpiece surface being finished ispreferred and a fixed abrasive finishing element surface layer whichapplies a uniform distribution of abrasive particles over the workpiecesurface being finished is more preferred.

A fixed abrasive finishing element surface layer and a finishing elementsubsurface layer free of finishing aids comprising a synthetic polymericis preferred. A synthetic polymeric layer comprising at least onematerial selected from the group consisting of an organic syntheticpolymer, an inorganic polymer, and combinations thereof is preferred. Apreferred example of organic synthetic polymer is an thermoplasticpolymer. Another preferred example of an organic synthetic polymer is athermoset polymer. An organic synthetic polymeric body comprisingorganic synthetic polymers including materials selected from the groupconsisting of polyurethanes, polyolefins, polyesters, polyamides,polystyrenes, polycarbonates, polyvinyl chlorides, polyimides, epoxies,chloroprene rubbers, ethylene propylene elastomers, butyl polymers,polybutadienes, polyisoprenes, EPDM elastomers, and styrene butadieneelastomers is preferred. Preferred stiff finishing surfaces can comprisepolyphenylene sulfide, polysulfone, and polyphenylene oxide polymers.Phenolic polymers can also be used. Polyolefin polymers are particularlypreferred for their generally low cost. A preferred polyolefin polymeris polyethylene. Another preferred polyolefin polymer is a propylenepolymer. Another preferred polyolefin polymer is a ethylene propylenecopolymer. Copolymer organic synthetic polymers are also preferred.Polyurethanes are preferred for the inherent flexibility informulations. A finishing element comprising a foamed organic syntheticpolymer is particularly preferred because of their flexibility andability to transport the finishing composition. A finishing elementcomprising a foamed polyurethane polymer is particularly preferred.Foaming agents and processes to foam organic synthetic polymers aregenerally known in the art. A finishing element comprising acompressible porous material is preferred and comprising a organicsynthetic polymer of a compressible porous material is more preferred.

A finishing element finishing surface layer substantially uniformwaymixture of a plurality of organic synthetic polymers can beparticularly tough, wear resistant, and useful. An organic syntheticpolymeric finishing element finishing surface comprising a plurality oforganic synthetic polymers and wherein the major component is selectedfrom materials selected from the group consisting of polyurethanes,polyolefins, polyesters, polyamides, polystyrenes, polycarbonates,polyvinyl chlorides, polyimides, epoxies, chloroprene rubbers, ethylenepropylene elastomers, butyl polymers, polybutadienes, polyisoprenes,EPDM elastomers, and styrene butadiene elastomers is preferred.Preferred stiff finishing surfaces can comprise polyphenylene sulfide,polysulfone, and polyphenylene oxide resins. Phenolic resins can also beused. The minor component is preferably also an organic syntheticpolymer and is preferably a modifying and/or toughening agent. Apreferred example of an organic synthetic polymer modifier is a materialwhich reduces the hardness or flex modulus of the finishing element bodysuch an polymeric elastomer. A compatibilizing agent can also be used toimprove the physical properties of the polymeric mixture.Compatibilizing agents are often also synthetic polymers and have polarand/or reactive functional groups such as carboxylic acid, maleicanhydride, and epoxy groups. Organic synthetic polymers of the abovedescriptions are generally available commercially. Illustrativenonlimiting examples of commercial suppliers of organic syntheticpolymers include Exxon Co., Dow Chemical, Sumitomo Chemical, and BASF.

A fixed abrasive finishing element comprising a synthetic polymercomposition having a plurality of layers is preferred. A fixed abrasivefinishing element comprising at least one layer of a soft syntheticpolymer is preferred. A fixed abrasive finishing element comprising atleast one layer of a elastomeric synthetic polymer is preferred. A fixedabrasive finishing element comprising at least one layer of a thermosetelastomeric synthetic polymer is preferred.

Further illustrative nonlimiting examples of preferred finishingelements for use in the invention are also discussed. A finishingelement having at least a layer of an elastomeric material having aShore A hardness of at least 30 A is preferred. ASTM D 676 is used tomeasure hardness. A porous finishing element is preferred to moreeffectively transfer the polishing slurry to the surface of theworkpiece being finished. A finishing element comprising a syntheticresin material is preferred. A finishing element comprising a thermosetresin material is more preferred. A finishing element having layers ofdifferent compositions is preferred to improve the operative finishingmotion on the workpiece surface being finished. As an example, afinishing element having two layers, one a hard layer and one a softlayer, can better transfer the energy of operative finishing motion tothe workpiece surface being finished than a similar thickness finishingelement of only a very soft layer. A thermoset synthetic resin is lessprone to elastic flow and thus is more stable in this application. Afinishing element which is thin is preferred because it generallytransfers the operative finishing motion to the workpiece surface beingfinished more efficiently. A finishing element having a thickness from0.5 to 0.002 cm is preferred and a thickness from 0.3 to 0.005 cm ismore preferred and a finishing element having a thickness from 0.2 to0.01 cm is even more preferred. Current synthetic resin materials can bemade quite thin now. The minimum thickness will be determined by thefinishing element's integrity and longevity during polishing which willdepend on such parameters as tensile and tear strength. A finishingelement having sufficient strength and tear strength for chemicalmechanical finishing is preferred.

An abrasive finishing element having a flex modulus in particular rangesis also preferred. An abrasive finishing element having a high flexmodulus is generally more efficient for planarizing. An abrasivefinishing element having a low flex modulus is generally more efficientfor polishing. Further a continuous belt fixed abrasive finishingelement can have a different optimum flex modulus than a fixed abrasivefinishing element disk. One also needs to consider the workpiece surfaceto be finished in selecting the flex modulus. A fixed abrasive finishingelement comprising a synthetic resin having flex modulus of at most1,000,000 psi is preferred and having flex modulus of at most 800,000psi is more preferred and 500,000 psi is more preferred. Pounds persquare in is psi. Flex modulus is preferably measured with ASTM 790 B at73 degrees Fahrenheit. Fixed abrasive finishing elements comprising asynthetic resin having a very low flex modulus are also generally knownto those skilled in the art such as elastomeric polyurethanes which canalso be used. A finishing element having a flex modulus of greater than1,000,000 psi can be preferred for some particular planarizingapplications.

For some embodiments, polishing pad designs and equipment such as inU.S. Pat. No. 5,702,290 to Leach, a polishing pad having a high flexuralmodulus can be effective and preferred. A finishing element having acontinuous phase of material imparting resistance to local flexing ispreferred. A preferred continuous phase of material is a syntheticpolymer, more preferably an organic synthetic polymer. An organicsynthetic polymer having a flexural modulus of at least 50,000 psi ispreferred and having a flexural modulus of at least 100,000 psi is morepreferred and having a flexural modulus of at least 200,000 psi is evenmore preferred for the continuous phase of synthetic polymer in thefinishing element. An organic synthetic polymer having a flexuralmodulus of at most 5,000,000 psi is preferred and having a flexuralmodulus of at most 3,000,000 psi is more preferred and having a flexuralmodulus of at most 2,000,000 psi is even more preferred for thecontinuous phase of synthetic polymer in the finishing element. Anorganic synthetic polymer having a flexural modulus of from 5,000,000 to50,000 psi is preferred and having a flexural modulus of from 3,000,000to 100,000 psi is more preferred and having a flexural modulus of atfrom 2,000,000 to 200,000 psi is even more preferred for the continuousphase of synthetic polymer in the finishing element. For some lessdemanding applications (such as die with a lower pattern density), aflexural modulus of at least 20,000 psi is preferred. These ranges offlexural modulus for the synthetic polymers provide useful performancefor finishing a semiconductor wafer and can improve local planarity inthe semiconductor. Flexural modulus is preferably measured with ASTM 790B at 73 degrees Fahrenheit. Pounds per square inch is psi.

An abrasive finishing element having Young's modulus in particularranges is also preferred. An abrasive finishing element having a highYoung's modulus is generally more efficient for planarizing. An abrasivefinishing element having a low Young's modulus is generally moreefficient for polishing. Further a continuous belt fixed abrasivefinishing element can have a different optimum Young's modulus than afixed abrasive finishing element disk. One also needs to consider theworkpiece surface to be finished in selecting the Young's modulus. For aflexible abrasive finishing element having a Young's modulus from 100 to700,000 psi (pounds per square in inch) is preferred and having aYoung's modulus from 300 to 200,000 psi (pounds per square in inch) ismore preferred and having a Young's modulus from 300 to 150,000 psi(pounds per square in inch) is even more preferred. Particularly stiffabrasive finishing elements can have a preferred Young's modulus of atleast 700,000 psi. For particularly flexible abrasive finishingelements, a Young's modulus of less than 100,000 psi are preferred andless than 50,000 psi is more preferred.

An abrasive finishing element having abrasive asperities on thefinishing element finishing surface is preferred. An abrasive finishingelement having abrasive asperities having a height from 0.9 to 0.005micrometers is preferred and an abrasive finishing element havingabrasive asperities having a height from 0.3 to 0.005 micrometers ismore preferred and an abrasive finishing element having abrasiveasperities having a height from 0.1 to 0.01 micrometers is even morepreferred and an abrasive finishing element having abrasive asperitieshaving a height from 0.05 to 0.005 micrometers is more particularlypreferred. the asperities are preferably firmly attached to thefinishing element finishing surface and asperities which are an integralpart of the finishing element finishing surface are more preferred. Anabrasive finishing element having small asperities can finish aworkpiece surface to fine tolerances.

Illustrative nonlimiting abrasive particles comprising silica, siliconnitride, alumina, and ceria are preferred. Fumed silica is particularlypreferred. A metal oxide is a type of preferred abrasive particle. Aparticularly preferred particulate abrasive is an abrasive selected fromthe group consisting of iron (III) oxide, iron (II) oxide, magnesiumoxide, barium carbonate, calcium carbonate, manganese dioxide, silicondioxide, cerium dioxide, cerium oxide, chromium (III) trioxide, andaluminum trioxide. Abrasive particles having an average diameter of lessthan 0.5 micrometers are preferred and less than 0.3 micrometer are morepreferred and less than 0.1 micrometer are even more preferred and lessthan 0.05 micrometers are even more particularly preferred. Abrasiveparticles having an average diameter of from 0.5 to 0.01 micrometer arepreferred and between 0.3 to 0.01 micrometer are more preferred andbetween 0.1 to 0.01 micrometer are even more preferred.

Abrasive particles having a different composition from the finishingelement body are preferred. An abrasive particle having a Knoop hardnessof less than diamond is particularly preferred to reduce microscratcheson workpiece surface being finished and a Knoop hardness of less than 50GPa is more particularly preferred and a Knoop hardness of less than 40GPa is even more particularly preferred and a Knoop hardness of lessthan 35 GPa is especially particularly preferred. An abrasive particlehaving a Knoop hardness of at least 1.5 GPa is preferred and having aKnoop hardness of at least 2 is preferred. An abrasive particle having aKnoop hardness of from 1.5 to 50 GPa is preferred and having a Knoophardness of from 2 to 40 GPa is preferred and having a Knoop hardness offrom 2 to 30 GPa is even more preferred. A fixed abrasive finishingelement having a plurality of abrasive particles having at least twodifferent Knoop hardnesses can be preferred.

A reinforcing layer or member can also be included with or attached tofinishing element finishing body. A finishing element having a finishingbody connected to a reinforcing layer is preferred and a finishingelement having a finishing body integral with a reinforcing layer ismore preferred. Preferred nonlimiting examples of reinforcing layers ormembers are fabrics, woven fabrics, film layers, and long fiberreinforcement members. A continuous belt can have substantiallycontinuous fibers therein. Aramid fibers are particularly preferred fortheir low stretch and excellent strength. The reinforcing layers canattached with illustrative generally known adhesives and variousgenerally known thermal processes such as extrusion coating or bonding.

The fixed abrasive firmly attached to the finishing element finishingsurface is preferred. The abrasive can be firmly attached to thefinishing element finishing surface with known adhesives and/or mixedinto a surface layer of a polymeric layer, preferably an organicpolymeric layer. Particular abrasive surface topographies can bepreferred for specific applications. Fixed abrasive finishing elementsare generally known to those skilled in the art. Some nonlimitingexamples include U.S. Pat. No. 4,966,245 to Callinan, U.S. Pat. No.5,823,855 to Robinson, U.S. Pat. No. 5,692,950 to Rutherford, WO98/06541 to Rutherford and WO 98/181159 to Hudson are included hereinfor general guidance and modification of fixed abrasive finishingelements by those skilled in the art.

FIG. 5 is an artist's representation of finishing some unwanted raisedregions and some regions below the unwanted raised regions. ReferenceNumeral 800 represents a portion of a semiconductor wafer surface havingtwo unwanted raised regions. Reference Numeral 802 represent unwantedraised regions on the semiconductor surface being finished. ReferenceNumeral 804 represent lower local regions on the semiconductor surfacebeing finished proximate to the unwanted raised regions. ReferenceNumeral 810 represents the finishing element finishing surface in localcontact with the unwanted raised regions (Reference Numeral 802).Reference Numeral 812 represents the finishing element surface localregion displaced from but proximate to and lower than the unwantedraised local regions. As shown the finishing element finishing surfacecan reduce pressure and/or lose actual contact with the lower localregions on the semiconductor proximate to the unwanted raised localregions. This leads to unwanted raised regions having higher pressurewhich in turn can reduce the lubricating boundary layer thickness in theunwanted raised regions. Reducing the boundary layer thickness generallyincreases local tangential friction forces, raises the finishing ratemeasured in angstroms per minute on the unwanted raised regions. Alsothe pressure in lower regions proximate the unwanted raised regions havelower pressure applied which in turn can increase lubricating boundarylayer thickness in these lower regions. Increasing the lubricatingboundary layer thickness generally decreases local tangential forceslowering the finishing rate measured in angstroms per minute in theselower regions proximate the unwanted raised regions. By increasingfinishing rate in the unwanted raised regions and lowering the finishingrate in the proximate lower regions the planarity of the semiconductoris generally improved. This generally helps the unwanted raised regionsto have higher finishing rates when measured in angstroms per minute andimproves within die nonuniformity. As shown in the FIG. 5, the region ofcontact with the unwanted raised region is small which in turn raisesthe finishing pressure applied by the finishing elements having a higherflexural modulus and this increased pressure increases the finishingrate measured in angstroms per minute at the unwanted raised region.This higher pressure on the unwanted raised region also increasesfrictional heat which can further increase finishing rate measured inangstroms per minute in the unwanted raised region. Boundary lubricationon the unwanted raised region can be reduced due to the highertemperature and/or pressure which further increases friction andfinishing rate measured in angstroms per minute. Higher stiffnessfinishing element finishing surfaces apply higher pressures to theunwanted raised local regions which can further improve planarization,finishing rates, and within die nonuniformity. Finishing using finishingelements of this in invention wherein the unwanted raised regions have afinishing rate measured in angstroms per minute of at least 1.6 timesfaster than in the proximate low local region measured in angstroms perminute is preferred and wherein the unwanted raised regions have afinishing rate of at least 2 times faster than in the proximate lowlocal region is more preferred and wherein the unwanted raised regionshave a finishing rate of at least 4 times faster than in the proximatelow local region is even more preferred. Where there is no contact withthe proximate low local region, the finishing rate in the low localregion can be very small and thus the ratio between the finishing ratein the unwanted raised region to finishing rate in the low local regioncan be large. Using boundary lubrication control methods of this ininvention wherein the unwanted raised regions have a finishing ratemeasured in angstroms per minute of from 1.6 to 500 times faster than inthe proximate low local region measured in angstroms per minute ispreferred and wherein the unwanted raised regions have a finishing rateof from 2 to 300 times faster than in the proximate low local region ismore preferred and wherein the unwanted raised regions have a finishingrate of from 2 to 200 times faster than in the proximate low localregion is even more preferred and wherein the unwanted raised regionshave a finishing rate of from 4 to 200 times faster than in theproximate low local region is even more preferred. By increasing thestiffness of the finishing element finishing surface, the pressureapplied to the unwanted raised region can be increased. Flexural modulusas measured by ASTM 790 B at 73 degrees Fahrenheit is a useful guide tohelp raise the stiffness of a polymer finishing element. By adjustingthe flexural modulus as measured by ASTM 790 B at 73 degrees Fahrenheitthe pressure can be increased on the unwanted raised regions to increasefinishing rates measured in Angstroms per minute. Applying at least twotimes higher pressure to the unwanted raised region when compared to theapplied pressure in a lower region proximate unwanted raised region ispreferred and applying at least three times higher pressure to theunwanted raised region when compared to the applied pressure in a lowerregion proximate unwanted raised region is more preferred and applyingfive times higher pressure to the unwanted raised region when comparedto the applied pressure in a lower region proximate unwanted raisedregion is even more preferred. Because the lower region proximate theunwanted raised region can have a very low pressure, at most 100 timeshigher pressure in the unwanted raised regions compared to the pressurein a lower region proximate the unwanted raised region is preferred andat most 50 times higher pressure in the unwanted raised regions comparedto the pressure in a lower region proximate the unwanted raised regionis more preferred. By adjusting the flexural modulus of the finishingelement finishing surface, lubricating boundary layer, and the othercontrol parameters discussed herein, finishing and planarization ofsemiconductor wafer surfaces can be accomplished. The lubricatingboundary layer will now be illustrated in FIG. 6.

FIG. 6 is an artist's representation of an example of the effects on theboundary layer lubrication discussed herein above. As discussed herein,it is not drawn to scale so the boundary layer thickness can beillustrated in simple fashion for helpful guidance. Reference Numeral800 represents a cross-sectional view of a semiconductor wafer havingtwo unwanted raised regions (Reference Numeral 802). Reference Numeral804 represents a cross-sectional view of a semiconductor wafer havinglower regions proximate to the two unwanted raised regions (ReferenceNumeral 802). Reference Numeral 900 represents the lubricating boundarylayer. Reference Numeral 902 represents thinner regions of lubricatingboundary layer (for instance having a thickness of 4 molecules). Notethat the thinner regions of a lubricating boundary layer can occurproximate the unwanted raised regions on the semiconductor wafer surfacebeing finished. Reference Numeral 904 represents a thicker region oflubricating boundary layer which can generally occur in regionsproximate to and below the unwanted raised regions. Reference Numeral820 represents a small cross-section of finishing element. The differentlocal regions having different lubricating boundary layers andlubricating properties is referred to herein as differential boundarylubrication. Differential lubricating boundary layers can improveplanarization for some semiconductor wafers (particularly at the dielevel).

Finishing aid

Supplying an effective amount of finishing aid from the finishingelement finishing surface layer, more preferably a lubricating aid,which reduces the coefficient of friction between the finishing elementfinishing surface and the workpiece surface being finished is preferred.Supplying an effective amount of finishing aid from the finishingelement finishing surface layer, more preferably a lubricating aid,which reduces the unwanted surface damage to the surface of theworkpiece being finished during finishing is preferred. Supplying aneffective amount of finishing aid from the finishing element finishingsurface layer, more preferably a lubricating aid, which differentiallylubricates different regions of the work piece and reduces the unwantedsurface damage to at least a portion of the surface of the workpiecebeing finished during finishing is preferred.

The finishing aid, more preferably a lubricating aid, can help reducethe formation of surface defects for high precision part finishing.Fluid based finishing aid, more preferably a lubricating aid, can helpreduction of brittle fracture at the workpiece surface being finished. Amethod of finishing which adds an effective amount of fluid basedfinishing aid, more preferably a lubricating aid, to the interfacebetween the finishing element finishing surface and workpiece surfacebeing finished is preferred. A preferred effective amount of fluid basedfinishing aid, more preferably a lubricating aid, reduces the occurrenceof unwanted surface defects. A preferred effective amount of fluid basedfinishing aid, more preferably a lubricating aid, can reduce thecoefficient of friction between the work piece surface being finishedand the finishing element finishing surface.

A lubricating aid which is water soluble is preferred. A lubricating aidwhich has a different solubility in water at different temperatures ismore preferred. A degradable finishing aid, more preferably alubricating aid, is also preferred and a biodegradable finishing aid,more preferably a lubricating aid, is even more preferred. Anenvironmentally friendly finishing aid, more preferably a lubricatingaid, is particularly preferred. A water based lubricant formed withwater which has low sodium content is also preferred because sodium canhave a adverse performance effect on the preferred semiconductor partsbeing made. A lubricant free of sodium is a preferred lubricant. As usedherein a lubricant fluid free of sodium means that the sodium content isbelow the threshold value of sodium which will adversely impact theperformance of a semiconductor wafer or semiconductor parts madetherefrom. A finishing aid, more preferably a lubricating aid, free ofsodium is preferred. As used herein a finishing aid free of sodium meansthat the sodium content is below the threshold value of sodium whichwill adversely impact the performance of a semiconductor wafer orsemiconductor parts made therewith.

Certain particularly important workpieces in the semiconductor industryhave regions of high conductivity and regions of low conductivity. Thehigher conductivity regions are often comprised of metallic materialssuch as tungsten, copper, aluminum, and the like. An illustrativeexample of a common lower conductivity region is silicon and siliconoxide. A fluid based lubrication which differentially lubricates the tworegions is preferred and a fluid based lubricant which substantiallydifferentially lubricates two regions is more preferred. An example of adifferential lubrication is if the coefficient of friction is changed bydifferent amounts in one region versus the other region duringfinishing. An example of differential lubrication is where the boundarylubricant reacts differently with different chemical compositions tocreate regions having different local regions of tangential frictionforce and different coefficients of friction. Another example is wherethe semiconductor surface being finished topography (for instanceunwanted raised regions) interact within the operative finishinginterface to create local regions having different tangential frictionforces and different coefficients of friction (see for example FIG. 5discussion herein). For instance one region (or area) can have thecoefficient of friction reduced by 20% and the other region (or area)reduced by 40%. This differential change in lubrication can be used tohelp in differential finishing of the two regions. An example ofdifferential finishing is a differential finishing rate between the tworegions. For example, a first region can have a finishing rate of “X”angstroms/minute and a second region can have a finishing rate of “Y”angstroms per minute before lubrication and after differentiallubrication, the first region can have a finishing rate of 80% of “X”and the second region can have a finishing rate of 60% of “Y”. Anexample of where this will occur is when the lubricant tends to adhereto one region because of physical or chemical surface interactions (suchas a metallic conductive region) and not adhere or not adhere as tightlyto the an other region (such as a non metallic, non conductive region).Different regions can have different lubricating boundary layerthicknesses. Changing the finishing control parameters to change thedifferential lubrication during finishing of the workpiece is apreferred method of finishing. Changing the finishing control parametersto change the differential lubrication during finishing of the workpiecewhich in turn changes the region finishing rates in the workpiece is amore preferred method of finishing. Changing the finishing controlparameters with in situ process control to change the differentiallubrication during finishing of the workpiece which in turn changes theregion finishing rates in the workpiece is an even more preferred methodof finishing. A secondary friction sensor probe can aid in an importantway in detecting and controlling differential lubrication in theworkpieces having heterogeneous surface compositions needing finishing.

A lubricating aid comprising a reactive lubricant is preferred. Alubricating aid comprising a boundary lubricant is also preferred. Areactive lubricant is a lubricant which chemically reacts with theworkpiece surface being finished. A boundary layer lubricant is apreferred example of a lubricant which can form a lubricating film onthe surface of the workpiece surface. As used herein a boundarylubricant is a thin layer on one or more surfaces which prevents or atleast limits, the formation of strong adhesive forces between theworkpiece being finished and the finishing element finishing surface andtherefore limiting potentially damaging friction junctions between theworkpiece surface being finished and the finishing element finishingsurface. A boundary layer film has a comparatively low shear strength intangential loading which reduces the tangential force of frictionbetween the workpiece being finished and the finishing element finishingsurface which can reduce surface damage to the workpiece being finished.In other words, boundary lubrication is a lubrication in which frictionbetween two surfaces in relative motion, such as the workpiece surfacebeing finished and the finishing element finishing surface, isdetermined by the properties of the surfaces, and by the properties ofthe lubricant other than the viscosity. Organic lubrication layerswherein the friction between two surfaces is dependent on lubricantproperties other than viscosity is preferred. Different regionalboundary layers on a semiconductor wafer surface being finished can bepreferred for some finishing—particularly planarizing. A boundary filmgenerally forms a thin film, perhaps even several molecules thick, andthe boundary film formation depends on the physical and chemicalinteractions with the surface. A boundary lubricant which forms of thinfilm is preferred. A boundary lubricant forming a film having athickness from 1 to 10 molecules thick is preferred and a boundarylubricant forming a film having a thickness from 1 to 6 molecules thickis more preferred and a boundary lubricant forming a film having athickness from 1 to 4 molecules thick is even more preferred. A boundarylubricant forming a film having a thickness from 1 to 10 molecules thickon at least a portion of the workpiece surface being finished isparticularly preferred and a boundary lubricant forming a film having athickness from 1 to 6 molecules thick on at least a portion of theworkpiece surface being finished is more particularly preferred and aboundary lubricant forming a film having a thickness from 1 to 4molecules thick on at least a portion of the workpiece surface beingfinished is even more particularly preferred. A boundary lubricantforming a film having a thickness of at most 10 molecules thick on atleast a portion of the workpiece surface being finished is particularlypreferred and a boundary lubricant forming a film having a thickness ofat most 6 molecules thick on at least a portion of the workpiece surfacebeing finished is more particularly preferred and a boundary lubricantforming a film having a thickness of at most 4 molecules thick on atleast a portion of the workpiece surface being finished is even moreparticularly preferred. An operative motion which continues in asubstantially uniform direction can improve boundary layer formation andlubrication. A discontinuous operative motion can be used to change thelubricating boundary layer. Boundary lubricants, because of the smallamount of required lubricant, are particularly effective finishing aidsfor inclusion in fixed abrasive finishing elements. The molecularthickness of lubricating boundary layers can be measured with generallyknown frictional force measures and/or energy change sensors discussedherein. Changing the pressure in the operative finishing interfaceand/or in the secondary friction sensor interface can be used todetermine molecular thickness. Controls can also be used by usingvarious generally known analytical techniques such as spectroscopy andthese results used to calibrate target energy change sensors andfrictional force measures. Thermal analysis can also be used to measurethe quantity of organic boundary layer on a surface and then thethickness calculated. Thermal analysis can be used to determine theefficacy of a particular lubricating boundary layer including solidboundary lubricant zone, boundary liquid lubricant zone, and boundarylubricant desorbed zone and the transition temperatures therebetween.

Heterogeneous lubricating boundary layers can improve finishing andplanarizing of some semiconductor wafers where a differential finishingrate is desired in different regions. A semiconductor wafer surfacehaving at least one unwanted raised region wherein the lubricatingboundary layer thickness is at most one half the molecular layerthickness of the lubricating boundary layer thickness proximate to theunwanted raised region is preferred. A semiconductor wafer surfacehaving at least one unwanted raised region wherein the boundarylubrication thickness is at most one third the molecular layer thicknessof the lubricating boundary layer thickness proximate to the unwantedraised region is more preferred. A semiconductor wafer surface having atleast one unwanted raised region wherein the lubricating boundary layerthickness is at most one quarter the molecular layer thickness of thelubricating boundary layer thickness proximate to the unwanted raisedregion is more preferred. Applications of this technology are furtherdiscussed herein elsewhere.

Controlling the thickness of the lubricating boundary layer by changingat least one control parameter in a manner that changes the tangentialforce of friction in at least one region of the semiconductor wafersurface in response to an in situ control signal is preferred.Controlling the thickness of the lubricating boundary layer by changingat least one control parameter in a manner that changes the tangentialforce of friction in at least two different regions of the semiconductorwafer surface in response to an in situ control signal is morepreferred. Preferably the unwanted raised regions are related to arepeating pattern in the semiconductor wafer die. A plurality of dieeach having the same repeating pattern on the semiconductor wafersurface being finished is preferred. These repeating patterns aregenerally created during semiconductor wafer manufacture and can berelated to pattern densities. This is because small changes inlubricating boundary layers can change finishing rate, finishing rateselectivity, and finished surface quality.

A reactive boundary lubricant is a preferred lubricant. A lubricatingboundary layer comprising physical adsorption (physisorption) of thelubricant molecules to the semiconductor surface being finished is apreferred lubricating boundary layer. Van der Waals surface forces are apreferred example of physical adsorption. Dipole—dipole interactionbetween the boundary lubricant and the semiconductor wafer surface beingfinished is a preferred example of physical adsorption. A reversibledipole—dipole interaction between the boundary lubricant and thesemiconductor wafer surface is an example of a more preferred physicaladsorption lubricating boundary layer. An organic alcohol is anillustrative preferred example. A polar organic molecule containing thehetereoatom oxygen is preferred. An organic boundary lubricating layerwhich is a solid film generally has a greater ability to separate thefinishing element finishing surface from the semiconductor wafer surfacebeing finished. A heat of adsorption of from 2,000 to 10,000 cal/mole ispreferred for physisorption. A physisorption organic boundarylubricating layer is a preferred reversible lubricating layer.

A lubricating boundary layer comprising chemisorption of lubricantmolecules to the semiconductor wafer being finished is a preferredlubricating boundary layer. In chemisorption, chemical bonds hold theboundary lubricants to the semiconductor wafer surface being finished.As an illustrative example, a reaction of stearic acid forms a “metalsoap” thin film on a metal surface. An organic carboxylic acid is apreferred example. Further, the “metal soap” can have a higher meltingtemperature and thus form regional areas of an organic boundary layerhaving higher temperature lubricating capacity as discussed furtherherein below. A heat of absorption of between 10,000 to 100,000 cal/moleis preferred for chemisorption.

A solid film organic boundary lubricating layer generally has a greaterability to separate the finishing element finishing surface from thesemiconductor wafer surface being finished. A solid film organicboundary lubricating layer can thus help reduce finishing rates asmeasured in angstroms per minute (compared to a liquid film). A liquidfilm organic boundary lubricating layer generally has a lower ability toseparate the finishing element finishing surface from the semiconductorwafer surface being finished can thus help increase finishing rates asmeasured in angstroms per minute (compared to a solid film). The sameboundary lubricant can form either solid film organic boundarylubricating layer or a liquid film organic boundary lubricating layerdepending on the operative finishing interface process conditions. Areversible organic boundary lubricating layer (which can change fromsolid to liquid to solid depending on processing conditions such astemperature) is preferred. Finishing a heterogeneous semiconductor wafersurface having at least one unwanted raised region wherein thelubricating boundary layer comprises a liquid film on the unwantedraised region and the lubricating boundary layer comprises a solid filmin the region below and proximate to the unwanted raised region ispreferred. Finishing a heterogeneous semiconductor wafer surface havingat least one unwanted raised region wherein the lubricating boundarylayer comprises a higher temperature liquid film on the unwanted raisedregion and the lubricating boundary layer comprises a lower temperaturesolid film in the region below and proximate to the unwanted raisedregion is preferred. Applying an operative finishing motion to theoperative finishing interface forming a heterogeneous temperatureprofile on the semiconductor wafer surface being finishing and whereinthe temperature is higher on a plurality of unwanted raised regions ofthe heterogeneous semiconductor wafer surface and the temperature islower proximate to and below the plurality of unwanted raised regions ofthe heterogeneous semiconductor wafer surface and further the pluralityof unwanted raised regions have a liquid lubricating films on them andthe regions proximate to and below the plurality of unwanted raisedregions solid lubricating films on them. See for instance ReferenceNumerals 802 (unwanted raised region) and 804 (region proximate to andbelow the unwanted raised region) for further helpful guidance. Anexample is octadecyl alcolhol forms a solid lubricant film on copper atabout 20 to 55 degrees centigrade and a liquid film on copper at about65 to 110 degrees centigrade. An organic boundary lubricating layer thatis capable of changing from a solid film to a liquid film in theoperative finishing interface temperature range during a finishing cycletime is preferred. An organic boundary lubricating layer that is capableof changing from a solid film to a different physical form in theoperative finishing interface temperature range during a finishing cycletime is preferred. An organic boundary lubricating layer that is capableof changing from a liquid film to a different physical form in theoperative finishing interface temperature range during a finishing cycletime is preferred. An organic boundary lubricating layer that is capableof changing from a solid film to a liquid film in the temperature rangefrom 20 to 100 degrees centigrade is more preferred. By increasing thefinishing rate in the unwanted raised region and lowering the finishingrate in the region proximate to and below the unwanted raised region,planarization can be improved. Changing the lubricating boundary layerfilm physical form by changing at least one lubrication controlparameter in situ based on feed back information from a lubricationcontrol subsystem having an energy change sensor is preferred.Controlling the lubricating boundary layer film physical form bychanging at least one lubrication control parameter in situ based onfeed back information from a lubrication control subsystem having anenergy change sensor is more preferred. Increasing temperature on theunwanted raised region on the semiconductor wafer surface compared tothe temperature on the region below the unwanted raised region formingthe lubricating boundary layer liquid film on the unwanted raised regionand the lubricating boundary layer solid film on at least a portion ofthe semiconductor wafer surface below the raised region is preferred.Increasing temperature with frictional heat on the unwanted raisedregion on the semiconductor wafer surface compared to the temperature onthe region below the unwanted raised region forming the lubricatingboundary layer liquid film on the unwanted raised region and thelubricating boundary layer solid film on at least a portion of thesemiconductor wafer surface below the raised region is more preferred.Using and controlling the lubricating boundary layer physical form canhelp customize finishing for the particular semiconductor wafers needingfinishing. The operative motion interacts with the lubricating boundarylayer in a new and useful way to finish a workpiece surface, preferablya semiconductor wafer surface.

A boundary lubricant which forms a thin lubricant film on the metalconductor portion of a workpiece surface being finished is particularlypreferred. A nonlimiting preferred group of example boundary lubricantsinclude at least one lubricant selected from the group consisting offats, fatty acids, esters, and soaps. A preferred group of boundarylubricants comprise organic boundary lubricants. Another preferred groupof boundary lubricants comprise organic synthetic lubricants. Aphosphorous containing compound can be an effective preferred boundarylubricant. A phosphate ester is an example of a preferred phosphorouscontaining compound which can be an effective boundary lubricant. Achlorine containing compound can be an effective preferred boundarylubricant. A sulfur containing compound can be an effective preferredboundary lubricant. A compound containing atoms selected from the groupconsisting of one or more of the following elements oxygen, fluorine, orchlorine can be an effective finishing aid. A synthetic organic polymercontaining atoms selected from the group consisting of one or more ofthe following elements oxygen, fluorine, or chlorine can be an effectivefinishing aid. A sulfated vegetable oil and sulfurized fatty acid soapsare preferred examples of a sulfur containing compound. A lubricantwhich reacts physically with at least a portion of the workpiece surfacebeing finished is a preferred lubricant. A lubricant which reactschemically with at least a portion of the workpiece surface beingfinished is often a more preferred lubricant because it is often a moreeffective lubricant and can also aid at times directly in the finishing.

A marginally effective lubricant between the workpiece being finishedand the finishing element finishing surface is preferred. As usedherein, a marginally effective lubricant is a lubricant and amount whichdoes not perfectly lubricant and stop all wear but allows some wearwhile reducing or eliminating especially deleterious wear.

Limited zone lubrication between the workpiece being finished and thefinishing element finishing surface is preferred. As used herein,limited zone lubricating is lubricating to reduce friction between twosurfaces while simultaneously having wear occur. Limited zonelubricating which simultaneously reduces friction between the operativefinishing interface while maintaining a cut rate on the workpiecesurface being finished is preferred. Limited zone lubricating whichsimultaneously reduces friction between the operative finishinginterface while maintaining an acceptable cut rate on the workpiecesurface being finished is more preferred. Limited zone lubricating whichsimultaneously reduces friction between the operative finishinginterface while maintaining a finishing rate on the workpiece surfacebeing finished is preferred. Limited zone lubricating whichsimultaneously reduces friction between the operative finishinginterface while maintaining an acceptable finishing rate on theworkpiece surface being finished is more preferred. Limited zonelubricating which simultaneously reduces friction between the operativefinishing interface while maintaining a planarizing rate on theworkpiece surface being finished is preferred. Limited zone lubricatingwhich simultaneously reduces friction between the operative finishinginterface while maintaining an acceptable planarizing rate on theworkpiece surface being finished is more preferred. Limited zonelubricating which simultaneously reduces friction between the operativefinishing interface while maintaining a polishing rate on the workpiecesurface being finished is preferred. Limited zone lubricating whichsimultaneously reduces friction between the operative finishinginterface while maintaining an acceptable polishing rate on theworkpiece surface being finished is preferred. Lubricant types andconcentrations are preferably controlled during limited zonelubricating. Limited zone lubricating offers the advantages ofcontrolled wear along with reduced unwanted surface damage.

Limited zone lubrication between the workpiece being finished and thefinishing element finishing surface is preferred. As used herein,limited zone lubricating is lubricating to reduce friction between twosurfaces while simultaneously having wear occur. Limited zonelubricating which simultaneously reduces friction between the operativefinishing interface while maintaining a cut rate on the workpiecesurface being finished is preferred. Limited zone lubricating whichsimultaneously reduces friction between the operative finishinginterface while maintaining an acceptable cut rate on the workpiecesurface being finished is more preferred. Limited zone lubricating whichsimultaneously reduces friction between the operative finishinginterface while maintaining a finishing rate on the workpiece surfacebeing finished is preferred. Limited zone lubricating whichsimultaneously reduces friction between the operative finishinginterface while maintaining an acceptable finishing rate on theworkpiece surface being finished is more preferred. Limited zonelubricating which simultaneously reduces friction between the operativefinishing interface while maintaining a planarizing rate on theworkpiece surface being finished is preferred. Limited zone lubricatingwhich simultaneously reduces friction between the operative finishinginterface while maintaining an acceptable planarizing rate on theworkpiece surface being finished is more preferred. Limited zonelubricating which simultaneously reduces friction between the operativefinishing interface while maintaining a polishing rate on the workpiecesurface being finished is preferred. Limited zone lubricating whichsimultaneously reduces friction between the operative finishinginterface while maintaining an acceptable polishing rate on theworkpiece surface being finished is preferred. Lubricant types andconcentrations are preferably controlled during limited zonelubricating. Limited zone lubricating offers the advantages ofcontrolled wear along with reduced unwanted surface damage.

Lubricants which are polymeric can be very effective lubricants. Aboundary lubricant comprising organic synthetic polymers are preferredlubricants. Supplying a lubricant to the interface of the workpiecesurface being finished and the finishing element finishing surfacewherein the lubricant is from 0.1 to 15% by weight of the total fluidbetween the interface is preferred and from 0.2 to 12% by weight of thetotal fluid between the interface is more preferred and from 0.3 to 12%by weight of the total fluid between the interface is even morepreferred and from 0.3 to 9% by weight of the total fluid between theinterface is even more particularly preferred. These preferred rangesare given for general guidance and help to those skilled in the art.Lubricants outside this range are currently believed to be useful butnot as economical to use.

A lubricant having a molecular weight of at least 250 is oftenpreferred. A lubricant having functional groups containing elementsselected from the group consisting of chlorine, sulfur, and phosphorousis preferred and a boundary lubricant having functional groupscontaining elements selected from the group consisting of chlorine,sulfur, and phosphorous is more preferred. A lubricant comprising afatty acid substance is a preferred lubricant. An preferred example of afatty substance is a fatty acid ester or salt. Fatty acid salts of plantorigin can be particularly preferred. A lubricant comprising a syntheticpolymer is preferred and a lubricant comprising a boundary lubricantsynthetic polymer is more preferred and a lubricant comprising aboundary lubricant synthetic polymer and wherein the synthetic polymeris water soluble is even more preferred. A polymer having a numberaverage molecular weight from 400 to 150,000 is preferred and having anumber average molecular weight from 1,000 to 100,000 is more preferredand having a number average molecular weight from 1,000 to 50,000 iseven more preferred.

A lubricant comprising a polyalkylene glycol polymer is a preferredcomposition. A polymer of polyoxyalkylene glycol monoacrylate orpolyoxyalkylene glycol monomethacrylate is very useful as a base oflubricant. A polyethylene glycol having a molecular weight of 200 to2000 is preferred. Polyglycol having a molecular weight of at least 600is preferred and a polgylcol having a molecular weight above 800 is morepreferred. Polyglycols selected from the group polymers consisting ofethylene oxide, propylene oxide, and butylene oxide and mixtures thereofare particularly preferred. A fatty acid ester can be an effectivelubricant. Polyglycol derivatives are also preferred. An amine modifiedpolyglycol is an example of a preferred polyglycol.

A preferred finishing aid is a lubricating aid which can be included inthe finishing element. A finishing aid distributed in at least a portionof the finishing element proximate the finishing element finishingsurface is preferred and a finishing aid distributed substantiallyuniformly in at least a portion of the finishing element proximate thefinishing element finishing surface is more preferred and a finishingaid distributed uniformly in at least a portion of the finishing elementproximate the finishing element finishing surface is even morepreferred. A finishing aid selected from the group consisting of liquidand solid lubricants and mixtures thereof is a preferred finishing aid.

A combination of a liquid lubricant and ethylene vinyl acetate,particularly ethylene vinyl acetate with 15 to 50% vinyl acetate byweight, can be a preferred effective lubricating aid additive. Preferredliquid lubricants include paraffin of the type which are solid at normalroom temperature and which become liquid during the production of thefinishing element. Typical examples of desirable liquid lubricantsinclude paraffin, naphthene, and aromatic type oils, e.g. mono- andpolyalcohol esters of organic and inorganic acids such as monobasicfatty acids, dibasic fatty acids, phthalic acid and phosphoric acid.

The lubricating aid can be contained in finishing element body indifferent preferred forms. A lubricating aid dispersed in an organicsynthetic polymer is preferred. A lubricating aid which is a liquidlubricant can be dispersed throughout the primary organic syntheticresin wherein the liquid lubricant effect of the binding of the fixedabrasive is carefully controlled. A fixed abrasive free a coating havingfinishing aids is preferred and fixed abrasive particles free of acoating having finishing aid is more preferred. A lubricating aiddispersed in a minor amount of organic synthetic polymer which is itselfdispersed in the primary organic synthetic polymer in discrete,unconnected regions is more preferred. As an illustrative example, alubricant dispersed in a minor amount of an ethylene vinyl acetate andwherein the ethylene vinyl acetate is dispersed in discrete, unconnectedregions in a polyacetal resin. A lubricating aid dispersed in discrete,unconnected regions in an organic synthetic polymer is preferred. Bydispersing the finishing aid and/or lubricating aids in a plurality ofdiscrete, unconnected regions, their impact on the binding of the fixedabrasive in the body of the fixed abrasive element is reduced oreliminated.

A polyglycol is an example of a preferred finishing aid. Preferredpolyglycols include glycols selected from the group consisting ofpolyethylene glycol, an ethylene oxide-propylene butyl ethers, adiethylene glycol butyl ethers, ethylene oxide-propylene oxidepolyglycol, a propylene glycol butyl ether, and polyol esters. A mixtureof polyglycols is a preferred finishing aid. Alkoxy ethers of polyalkylglycols are preferred finishing aids. An ultra high molecular weightpolyethylene, particularly in particulate form, is an example ofpreferred finishing aid. A fluorocarbon resin is an example of apreferred lubricating agent. Fluorocarbons selected from the groupconsisting of polytetrafluoroethylene (PTFE), ethylenetetrafluoride/propylene hexafluoride copolymer resin (FEP), an ethylenetetrafluoride/perfluoroalkoxyethylene copolymer resin (PFA), an ethylenetetra fluoride/ethylene copolymer resin, a trifluorochloroethylenecopolymer resin (PCTFE), and a vinylidene fluoride resin are examples ofpreferred fluorocarbon resin finishing aids. A polyphenylene sulfidepolymer is a preferred polymeric lubricating aid.Polytetrafluoroethylene is a preferred finishing aid.Polytetrafluoroethylene in particulate form is a more preferredfinishing aid and polytetrafluoroethylene in particulate form whichresists reaggolmeration is a even more preferred finishing aid. Asilicone oil is a preferred finishing aid. A polypropylene is apreferred finishing aid, particularly when blended with polyamide andmore preferably a nylon 66. A lubricating oil is a preferred finishingaid. A polyolefin polymer can be a preferred effective lubricating aid,particularly when incorporated into polyamide resins and elastomers. Ahigh density polyethylene polymer is a preferred polyolefin resin. Apolyolefin/polytetrafluoroethylene blend is also a preferred lubricatingaid. Low density polyethylene can be a preferred lubricating aid. Afatty acid substance can be a preferred lubricating aid. An examples ofa preferred fatty acid substance is a fatty ester derived from a fattyacid and a polyhydric alcohol. Examples fatty acids used to make thefatty ester are lauric acid, tridecylic acid, myristic acid,pentadecylic acid, palmitic acid, margaric acid, stearic acid,nonadecylic acid, arachidic acid, oleic acid, elaidic acid and otherrelated naturally occurring fatty acids and mixtures thereof. Examplesof preferred polyhydric alcohols include ethylene glycol, propyleneglycol, homopolymers of ethylene glycol and propylene glycol or polymersand copolymers thereof and mixtures thereof.

Illustrative, nonlimiting examples of finishing aids include organicsynthetic resin systems and general useful related technology are givenin the U.S. Pat. Nos. 3,287,288 to Reilling, 3,458,596 to Eaigle,4,877,813 to Jimo et. al., 5,079,287 to Takeshi et. al., 5,110,685 toCross et. al., 5,216,079 to Crosby et. al., 5,523,352 to Janssen, and5,591,808 to Jamison and are included herein by reference in theirentirety for guidance and modification as appropriate by those skilledin the art. Some preferred suppliers of lubricants include Dow Chemical,Huntsman Corporation, and Chevron Corporation.

Generally those skilled in the art know how to measure the kineticcoefficient of friction. A preferred method is ASTM D 3028 - 95 and ASTMD 3028-95 B is particularly preferred. Those skilled in the art canmodify ASTM D 3028-95 B to adjust to appropriate finishing velocitiesand to properly take into consideration appropriate fluid effects due tothe lubricant and finishing composition. Preferred lubricants andfinishing compositions do not corrode the workpiece or localized regionsof the workpiece. Corrosion can lead to workpiece failure even beforethe part is in service. ASTM D 130 is a is a useful test for screeninglubricants for particular workpieces and workpiece compositions. As anexample of a metal strip such as a copper strip is cleaned and polishedso that no discoloration or blemishes detectable. The finishingcomposition to be tested is then added to a test tube, the copper stripis immersed in the finishing composition and the test tube is thenclosed with a vented stopper. The test tube is then heated undercontrolled conditions for a set period of time, the metal strip isremoved, the finishing composition removed, and the metal strip iscompared to standards processed under identical conditions to judge thecorrosive nature and acceptableness of the finishing composition. ASTM D1748 can also be used to screen for corrosion. Alternately a solidlubricant can be deposited on a surface to be screened for corrosiveeffects and the target sample tested under appropriate conditions. Thesetest methods are included herein by reference in their entirety.

Supplying an effective marginal lubrication to the interface between theworkpiece surface being finished and the finishing element finishingsurface is preferred and supplying an effective marginal boundarylubrication to the interface between the workpiece surface beingfinished and the finishing element finishing surface is more preferred.Marginal lubrication is less than complete lubrication and facilitatescontrolling frictional wear and tribochemical reactions. Independentcontrol of the lubricant control parameters aids in controlling aneffective amount of marginal lubrication and in situ control of thelubricant control parameters is more preferred.

Stabilizing fillers

A fibrous filler is a preferred stabilizing filler for the finishingelement finishing surface layer of this invention. A plurality ofsynthetic fibers are particularly preferred fibrous filler. Fibrousfillers tend to help generate a lower abrasion coefficient and/orstabilize the finishing element finishing surface from excessive wear.By reducing wear the finishing element has improved stability duringfinishing.

A preferred stabilizing filler is a dispersion of fibrous fillermaterial dispersed in the finishing element body. An organic syntheticresin fibers are a preferred fibrous filler. Preferred fibrous fillersinclude fibers selected from the group consisting of aramid fibers,polyester fibers, and polyamide fibers. Preferably the fibers have afiber diameter of from 1 to 15 microns and more preferably, from 1 to 8microns. Preferably the fibers have a length of less than 1 cm and morepreferably a length from 0.1 to 0.6 cm and even more preferably a lengthfrom 0.1 to 0.3 cm. Particularly preferred are short organic syntheticresin fibers that can be dispersed in the finishing element and morepreferably mechanically dispersed in at least a portion of the finishingelement proximate the finishing element finishing surface and morepreferably, mechanically substantially uniformly dispersed in at least aportion of the finishing element proximate the finishing elementfinishing surface and even more preferably and even more preferably,mechanically substantially uniformly dispersed in at least a portion ofthe finishing element proximate the finishing element finishing surface.The short organic synthetic fibers are added in the form of short fiberssubstantially free of entanglement and dispersed in the finishingelement matrix. Preferably, the short organic synthetic fibers comprisefibers of at most 0.6 cm long and more preferably 0.3 cm long. Anaromatic polyamide fiber is particularly preferred. Aromatic polyamidefibers are available under the tradenames of “Kevlar” from DuPont inWilmington, Del. and “Teijin Cornex” from Teijin Co. Ltd. The organicsynthetic resin fibers can be dispersed in the synthetic by methodsgenerally known to those skilled in the art. As a nonlimiting example,the cut fibers can be dispersed in a thermoplastic synthetic resinparticles of under 20 mesh, dried, and then compounded in a twin screw,counter rotating extruder to form extruded pellets having a size of from0.2-0.3 cm. Optionally, the pellets can be water cooled, as appropriate.These newly formed thermoplastic pellets having substantially uniformdiscrete, dispersed, and unconnected fibers can be used to extruded orinjection mold a fixed abrasive element of this invention. Aramid powdercan also be used to stabilize the finishing element organic syntheticpolymers to wear. Organic synthetic resin fibers are preferred becausethey tend to reduce unwanted scratching to the workpiece surface.

U.S. Pat. Nos. 4,877,813 to Jimmo, 5,079,289 to Takeshi et. al., and5,523,352 to Janssen are included herein by reference in its entiretyfor general guidance and appropriate modification by those skilled inthe art.

Workpiece

A workpiece needing finishing is preferred. A homogeneous surfacecomposition is a workpiece surface having one composition throughout andis preferred for some applications. A workpiece needing polishing ispreferred. A workpiece needing planarizing is especially preferred. Aworkpiece having a microelectronic surface is preferred. A workpiecesurface having a heterogeneous surface composition is preferred. Aheterogeneous surface composition has different regions with differentcompositions on the surface, further the heterogeneous composition canchange with the distance from the surface. Thus finishing can be usedfor a single workpiece whose surface composition changes as thefinishing process progresses. A workpiece having a microelectronicsurface having both conductive regions and nonconductive regions is morepreferred and is an example of a preferred heterogeneous workpiecesurface. Illustrative examples of conductive regions can be regionshaving copper or tungsten and other known conductors, especiallymetallic conductors. Metallic conductive regions in the workpiecesurface consisting of metals selected from the group consisting ofcopper, aluminum, and tungsten or combinations thereof are particularlypreferred. A semiconductor device is a preferred workpiece. A substratewafer is a preferred workpiece. A semiconductor wafer having a polymericlayer requiring finishing is preferred because a lubricating aid can beparticularly helpful in reducing unwanted surface damage to the softerpolymeric surfaces. An example of a preferred polymer is a polyimide.Polyimide polymers are commercially available from E. I. DuPont Co. inWilmington, Del. A semiconductor having a interlayer dielectric needingfinishing is preferred.

This invention is particularly preferred for workpieces requiring ahighly flat surface. Finishing a workpiece surface to a surface to meetthe specified semiconductor industry circuit design rule is preferredand finishing a workpiece surface to a surface to meet the 0.35micrometers feature size semiconductor design rule is more preferred andfinishing a workpiece surface to a surface to meet the 0.25 micrometersfeature size semiconductor design rule is even more preferred andfinishing a workpiece surface to a to meet the 0.18 micrometerssemiconductor design rule is even more particularly preferred. Anelectronic wafer finished to meet a required surface flatness of thewafer device rule in to be used in the manufacture of ULSIs (Ultra LargeScale Integrated Circuits) is a particularly preferred workpiece madewith a method according to preferred embodiments of this invention. Thedesign rules for semiconductors are generally known to those skilled inthe art. Guidance can also be found in the “The National TechnologyRoadmap for Semiconductors” published by SEMATECH in Austin, Tex.

A semiconductor wafer having a diameter of at least 200 mm is preferredand a semiconductor wafer having a diameter of at least 300 mm is morepreferred.

Finishing composition

Finishing compositions are generally known for fixed abrasive finishing.A chemical mechanical polishing slurry can also be used as finishingcomposition. Alternately, a finishing composition can be modified bythose skilled in the art by removing the abrasive particles to form afinishing composition free of abrasive particles. A finishingcomposition substantially free of abrasive particles is preferred and afinishing composition free of abrasive particles is more preferred.Finishing compositions have their pH adjusted carefully, and generallycomprise other chemical additives are used to effect chemical reactionsand/other surface changes to the workpiece. A finishing compositionhaving dissolved chemical additives is particularly preferred.Illustrative examples preferred dissolved chemical additives includedissolved acids, bases, buffers, oxidizing agents, reducing agents,stabilizers, and chemical reagents. A finishing composition having achemical which substantially reacts with material from the workpiecesurface being finished is particularly preferred. A finishingcomposition having a chemical which selectively chemically reacts withonly a portion of the workpiece surface is particularly preferred. Afinishing composition having a chemical which preferentially chemicallyreacts with only a portion of the workpiece surface is particularlypreferred.

Some illustrative nonlimiting examples of polishing slurries which canbe used and/or modified by those skilled in the art are now discussed.An example slurry comprises water, a solid abrasive material and a thirdcomponent selected from the group consisting of HNO₃, H₂SO₄, and AgNO₃or mixtures thereof. Another polishing slurry comprises water, aluminumoxide, and hydrogen peroxide mixed into a slurry. Other chemicals suchas KOH (potassium hydroxide) can also be added to the above polishingslurry. Still another illustrative polishing slurry comprises H₃PO₄ atfrom about 0.1% to about 20% by volume, H₂O₂ at from 1% to about 30% byvolume, water, and solid abrasive material. Still another polishingslurry comprises an oxidizing agent such as potassium ferricyanide, anabrasive such as silica, and has a pH of between 2 and 4. Still anotherpolishing slurry comprises high purity fine metal oxides particlesuniformly dispersed in a stable aqueous medium. Still another polishingslurry comprises a colloidal suspension of SiO₂ particles having anaverage particle size of between 20 and 50 nanometers in alkalisolution, demineralized water, and a chemical activator. Energy changesensors are a preferred type of sensor for feed back of in situ controlinformation. U.S. Pat. Nos. 5,209,816 to Yu et. al. issued in 1993,5,354,490 to Yu et. al. issued in 1994, 5,?5408,810 to Sandhu et. al.issued in 1996, 5,516,346 to Cadien et. al. issued in 1996, 5,527,423 toNeville et. al. issued in 1996, 5,622,525 to Haisma et. al. issued in1997, and 5,645,736 to Allman issued in 1997 comprise illustrativenonlimiting examples of slurries contained herein by reference in theirentirety for further general guidance and modification by those skilledin the arts. Commercial CMP polishing slurries are also available fromRodel Manufacturing Company in Newark, Del. Application WO 98/18159 toHudson gives general guidance for those skilled in the art for modifyingcurrent slurries to produce an abrasive free finishing composition.

In a preferred mode, the finishing composition is free of abrasiveparticles. However as the fixed abrasive finishing element wears downduring finishing, some naturally worn fixed abrasive particles can beliberated from the fixed abrasive finishing element can thus temporarilybe present in the finishing composition until drainage or removal.

Operative finishing motion

Chemical mechanical finishing during operation has the finishing elementin operative finishing motion with the surface of the workpiece beingfinished. A relative lateral parallel motion of the finishing element tothe surface of the workpiece being finished is an operative finishingmotion. Lateral parallel motion can be over very short distances ormacro-distances. A parallel circular motion of the finishing elementfinishing surface relative to the workpiece surface being finished canbe effective. A tangential finishing motion can also be preferred. U.S.Pat. Nos. 5,177,908 to Tuttle issued in 1993, 5,234,867 to Schultz et.al. issued in 1993, 5,522,965 to Chisholm et. al. issued in 1996,5,735,731 to Lee in 1998, and 5,962,947 to Talieh issued in 1997comprise illustrative nonlimiting examples of operative finishing motioncontained herein by reference in their entirety herein for furthergeneral guidance of those skilled in the arts.

Some illustrative nonlimiting examples of preferred operative finishingmotions for use in the invention are also discussed. This invention hassome particularly preferred operative finishing motions of the workpiecesurface being finished and the finishing element finishing surface.Moving the finishing element finishing surface in an operative finishingmotion to the workpiece surface being finished is a preferred example ofan operative finishing motion. Moving the workpiece surface beingfinished in an operative finishing motion to the finishing elementfinishing surface is a preferred example of an operative finishingmotion. Moving the finishing element finishing surface in a parallelcircular motion to the workpiece surface being finished is a preferredexample of an operative finishing motion. Moving the workpiece surfacebeing finished in a parallel circular motion to the finishing elementfinishing surface is a preferred example of an operative parallel.Moving the finishing element finishing surface in a parallel linearmotion to the workpiece surface being finished is a preferred example ofan operative finishing motion. Moving the workpiece surface beingfinished in a parallel linear motion to the finishing element finishingsurface is a preferred example of an operative parallel. The operativefinishing motion performs a significant amount of the polishing andplanarizing in this invention.

High speed finishing of the workpiece surface with fixed abrasivefinishing elements can cause surface defects in the workpiece surfacebeing finished at higher than desirable rates because of the higherforces generated. As used herein, high speed finishing involves relativeoperative motion having an equivalent linear velocity of greater than300 feet per minute and low speed finishing involves relative operativemotion having an equivalent linear velocity of at most 300 feet perminute. The relative operative speed is measured between the finishingelement finishing surface and the workpiece surface being finished.Supplying a lubricating aid between the interface of finishing elementfinishing surface and the workpiece surface being finished when highspeed finishing is preferred to reduce the level of surface defects.Supplying a lubricating aid between the interface of a fixed abrasivecylindrical finishing element and a workpiece surface being finished isa preferred example of high speed finishing. Supplying a lubricating aidbetween the interface of a fixed abrasive belt finishing element and aworkpiece surface being finished is a preferred example of high speedfinishing. Nonlimiting illustrative examples of a belt finishing elementand a cylindrical finishing element are found in patents U.S. Pat. No.5,735,731 to Lee and U.S. Pat. No. 5,762,536 to Pant and which can bemodified by those skilled in the art as appropriate. U.S. Pat. No.5,735,731 to Lee and U.S. Pat. No. 5,762,536 to Pant are included hereinby reference in their entirety.

Platen

The platen is generally a stiff support structure for the finishingelement. The platen surface facing the workpiece surface being finishedis parallel to the workpiece surface being planarized and is flat andgenerally made of metal. The platen reduces flexing of the finishingelement by supporting the finishing element, optionally a pressuredistributive element can also be used. The platen surface duringpolishing is in operative finishing motion to the workpiece surfacebeing finished. The platen surface can be static while the workpiecesurface being finished is moved in an operative finishing motion. Theplaten surface can be moved in a parallel motion fashion while theworkpiece surface being finished is static. Optionally, both the platensurface and the workpiece being finished can be in motion in a way thatcreates operative finishing motion between the workpiece and thefinishing element. Other types of platens are generally known in theindustry and functional.

Base support structure

The base support structure forms structure which can indirectly aid inapplying pressure to the workpiece surface being finished. It generallyforms a support surface for those members attached to it directly oroperatively connected to the base support structure. Other types of basesupport structure are generally known in the industry and functional.

Workpiece finishing sensor

A workpiece finishing sensor is a sensor which senses the finishingprogress to the workpiece in real time so that an in situ signal can begenerated. A workpiece finishing sensor is preferred. A workpiecefinishing sensor which facilitates measurement and control of finishingin this invention is preferred. A workpiece finishing sensor probe whichgenerates a signal which can be used cooperatively with the secondaryfriction sensor signal to improve finishing is more preferred.

The change in friction during finishing can be accomplished usingtechnology generally familiar to those skilled in the art. A change infriction can be detected by rotating the workpiece being finished andthe finishing element finishing surface with electric motors andmeasuring current changes on one or both motors. The current changesrelated to friction changes can then be used to produce a signal tooperate the finishing control subsystem. A change in friction can bedetected by rotating the workpiece finishing surface with the finishingelement finishing surface with electric motors and measuring powerchanges on one or both motors. Changes in friction can also be measuredwith thermal sensors. A thermistor is a non-limiting example ofpreferred non-optical thermal sensor. A thermal couple is anotherpreferred non-optical thermal sensor. An optical thermal sensor is apreferred thermal sensor. A infrared thermal sensor is a preferredthermal sensor. A sensors to measure friction in workpieces beingfinished are generally known to those skilled in the art. Non limitingexamples methods to measure friction in friction sensor probes aredescribed in the following U.S. Pat. Nos. 5,069,002 to Sandhu et. al.,5,196,353 to Sandhu, 5,308,438 to Cote et. al., 5,595,562 to Yau et.al., 5,597,442 to Chen, ?564,050 to Chen, and 5,738,562 to Doan et. al.and are included by reference herein in their entirety for guidance andcan be advantageously modified by those skilled in the art for use inthis invention. Thermal sensors are available commercially from TerraUniversal, Inc. in Anaheim, Calif. and Hart Scientific in American Fork,Utah. Measuring the changes in friction at the interface between theworkpiece being finished and the finishing element finishing surface togenerate an in situ signal for control is particularly preferred becausethe it can be effectively combined with the a secondary friction sensorfurther improve finishing control.

A workpiece finishing sensor for the workpiece being finished ispreferred. A sensor for the workpiece being finished selected from thegroup consisting of friction sensors, thermal sensors, optical sensors,acoustical sensors, and electrical sensors are preferred sensors for theworkpiece being finished in this invention. Workpiece thermal sensorsand workpiece friction sensors are non-limiting examples of preferredworkpiece friction sensors. As used herein, a workpiece friction sensorcan sense the friction between the interface of the workpiece beingfinished and the finishing element finishing surface during operativefinishing motion.

Additional non-limiting preferred examples of workpiece finishingsensors will now be discussed. Preferred optical workpiece finishingsensors are discussed. Preferred non-optical workpiece finishing sensorsare also discussed. The endpoint for planarization can be effected bymonitoring the ratio of the rate of insulator material removed over aparticular pattern feature to the rate of insulator material removalover an area devoid of an underlying pattern. The endpoint can bedetected by impinging a laser light onto the workpiece being polishedand measuring the reflected light versus the expected reflected light asan measure of the planarization process. A system which includes adevice for measuring the electrochemical potential of the slurry duringprocessing which is electrically connected to the slurry, and a devicefor detecting the endpoint of the process, based on upon theelectrochemical potential of the slurry, which is responsive to theelectrochemical potential measuring device. Endpoint detection can bedetermined by an apparatus using an interferometer measuring device todirect at an unpatterned die on the exposed surface of the wafer todetect oxide thickness at that point. A semiconductor substrate and ablock of optical quartz are simultaneously polished and aninterferometer, in conjunction with a data processing system are thenused to monitor the thickness and the polishing rate of the opticalblock to develop an endpoint detection method. A layer over a patternedsemiconductor is polished and analyzed using optical methods todetermine the end point. An energy supplying means for supplyingprescribed energy to the semiconductor wafer are used to develop adetecting means for detecting a polishing end point tot the polishing offilm by detecting a variation of the energy supplied tot thesemiconductor wafer. The use of sound waves can be used during chemicalmechanical polishing by measuring sound waves emanating from thechemical mechanical polishing action of the substrate against thefinishing element. A control subsystem can maintain a wafer count,corresponding to how many wafers are finished and the control subsystemregulates the backside pressure applied to each wafer in accordance witha predetermined function such that the backside pressure increasesmonotonically as the wafer count increases. The above methods aregenerally known to those skilled in the art. U.S. Pat. Nos. 5,081,796 toSchultz, 5,439,551 to Meikle et al., 5,461,007 to Kobayashi, 5,413,941to Koos et. al., 5,637,185 Murarka et al., 5,643,046 Katakabe et al.,5,643,060 to Sandhu et al., 5,653,622 to Drill et al., and 5,705,435 toChen. are included by reference in their entirety and included hereinfor general guidance and modification by those skilled in the art.

Changes in lubrication, particularly active lubrication, at theoperative finishing interface can significantly affect finishing ratesand finishing performance in ways that current workpiece finishingsensors cannot handle as effectively as desired. For instance, currentworkpiece finishing sensors are less effective for monitoring andcontrolling multiple real time changes in lubrication, particularlyactive lubrication, and changes in finishing such as finishing rates.This renders prior art workpiece finishing sensors less effective forlubricating boundary layer for controlling and stopping finishing wherefriction is adjusted or changed in real time. Secondary friction sensorsubsystems as indicated above can help to improve real time controlwherein the lubrication is changed during the finishing cycle time.Preferred secondary friction sensors include optical friction sensorsand non-optical friction sensors. An optical friction sensor is apreferred friction sensor. Non-limiting preferred examples of opticalfriction sensors is an infrared thermal sensing unit such as a infraredcamera and a laser adjusted to read minute changes of movement frictionsensor probe to a perturbation. A non-optical sensing friction sensor isa preferred friction sensor. Non-limiting preferred examples ofnon-optical friction sensors include thermistors, thermocouples, diodes,thin conducting films, and thin metallic conducting films. Electricalperformance versus temperature such as conductivity, voltage, andresistance is measured. Those skilled in the thermal measurement artsare generally familiar with non-optical thermal sensors and their use. Achange in friction can be detected by rotating the friction sensor inoperative friction contact with the finishing element finishing surfacewith electric motors and measuring current changes on one or bothmotors. The current changes related to friction changes can then be usedto produce a signal to operate the friction sensor subsystem. Secondaryfriction detectors can be used to sense changes in friction andtangential friction forces. Some illustrative secondary friction sensormotions are pulsed direction changes, pulsed pressure changes,continuous motion such as circular, elliptical, and linear. An operativesecondary friction sensor motion is an operative secondary frictionsensor motion between the secondary friction sensor surface and thefinishing element finishing surface. An absolute motion of the secondaryfriction sensor is preferred. A secondary friction detector comprises aprobe that can sense friction at the interface between a material whichis separated from the workpiece surface being finished. A preferredsecondary friction detector is friction sensor probe. A friction sensorprobe comprises a probe that can sense friction at the interface betweena material which is separate and unconnected to the workpiece surfacebeing finished and the finishing element finishing surface. Details ofsecondary friction sensors and their use is found in Provisional PatentApplication with PTO Ser. No. 60/107,300, private serial numberNDTLBD1198a filed on the Nov. 6, 1998 and having the title “In SituFriction Detector for finishing workpieces” and in a Regular PatentApplication with private serial number 1DTL11599 filed on the same dateas this application and having the title “In Situ Friction Detector forfinishing semiconductor wafers” and they are included in their entiretyby reference for general guidance and modification of those skilled inthe art. Where the material changes with depth during the finishing ofworkpiece being finished, one can monitor friction changes with thesecondary friction sensor having dissimilar materials even with activelubrication and therefore readily detect the end point. As an additionalexample, the finishing rate can be correlated with the instantaneouslubrication at the operative finishing interface, a mathematicalequation can be developed to monitor finishing rate with instantaneouslubrication information from the secondary sensor and the processor thenin real time calculates finishing rates and indicates the end point tothe controller.

Process control parameters

Preferred process control parameters include those control parameterswhich can be changed during processing and affect workpiece finishing.Control of the operative finishing motion is a preferred process controlparameter. Examples of preferred operative finishing motions includerelative velocity, pressure, and type of motion. Examples of preferredtypes of operative finishing motion include tangential motion, planarfinishing motion, linear motion, vibrating motion, oscillating motion,and orbital motion. Finishing temperature is a preferred process controlparameter. Finishing temperature can be controlled by changing the heatsupplied to the platen or heat supplied to the finishing composition.Alternately, friction can also change the finishing temperature and canbe controlled by changes in lubrication, applied pressure duringfinishing, and relative operative finishing motion velocity. Changes inlubricant can be effected by changing finishing composition(s) and/orfeed rate(s). A preferred group of process control parameters consistsof parameters selected from the group consisting of wafer relativevelocity, platen velocity, polishing pattern, finishing temperature,force exerted on the operative finishing interface, finishingcomposition, finishing composition feed rate, and finishing padconditioning.

Processor

A processor is preferred to help evaluate the workpiece finishing sensorinformation. A processor can be a microprocessor, an ASIC, or some otherprocessing means. Processor preferably has computational and digitalcapabilities. Non limiting examples of processing information includeuse of various mathematical equations, calculating specific parameters,memory look-up tables or databases for generating certain parameterssuch as historical performance or preferred parameters or constants,neural networks, fuzzy logic techniques for systematically computing orobtaining preferred parameter values. Input parameter(s) can includeinformation on current wafers being polished such as uniformity,expected polish rates, preferred lubricants(s), preferred lubricantconcentrations, entering film thickness and uniformity, workpiecepattern. Further preferred non-limiting processor capabilities includingadding, subtracting, multiplying, dividing, use functions, look-uptables, noise subtraction techniques, comparing signals, and adjustingsignals in real time from various inputs and combinations thereof.

Use of information for feedback and controller

Controllers to control the finishing of workpieces are generally knownin the art. Controllers generally use information at least partiallyderived from the processor to make changes to the process controlparameters. A processor is preferably operatively connected to a sensorto gain current information about the process and the processor is alsooperatively connected to a controller which preferably controls thefinishing control parameters. As used herein, a control subsystem is acombination of an operative sensor operatively connected to a processorwhich is operatively connected to a controller which in turn can changefinishing control parameters.

An advantage of this invention is the additional degree of control itgives to the operator performing planarization and/or polishing. Tobetter utilize this control, the use of feedback information to controlthe finishing control parameters is preferred and in situ control ismore preferred. Controlling the finishing control parameters selectedfrom the group consisting of finishing composition feed rates, finishingcomposition concentration, operative finishing motion, and operativefinishing pressure is preferred to improve control of the finishing ofthe workpiece surface being finished and in situ control is moreparticularly preferred. Another preferred example of an finishingcontrol parameter is to use a different finishing element for adifferent portion the finishing cycle time such as one finishing elementfor the planarizing cycle time and a different finishing element for thepolishing cycle time. Workpiece film thickness, measuring apparatus, andcontrol methods are preferred methods of control. Mathematical equationsincluding those developed based on process results can be used.Finishing uniformity parameters selected from the group consisting ofTotal Thickness Variation (TTV), Focal plane deviation (FPD),Within-Wafer Non-Uniformity (WIW NU), and surface quality are preferred.Average cut rate is a preferred finishing rate control parameter.Average finishing rate is a preferred finishing rate control parameter.Controlling finishing for at least a portion of the finishing cycle timewith a finishing sensor subsystem to adjust in situ at least onefinishing control parameter that affect finishing results is a preferredmethod of control finishing. Information feedback subsystems aregenerally known to those skilled in the art. Illustrative non limitingexamples of wafer process control methods include U.S. Pat. Nos.5,483,129 to Sandhu issued in 1996, 5,483,568 to Yano issued in 1996,5,627,123 to Mogi issued in 1997, 5,653,622 to Drill issued in 1997,5,657,123 to Mogi issued in 1997, 5,667,629 to Pan issued in 1997, and5,695,601 to Kodera issued in 1997 are included herein for guidance andmodification by those skilled in the art and are included herein byreference in their entirety.

Controlling at least one of the finishing control parameters based onusing secondary friction sensor information combined with workpiecefinishing sensor information is preferred and controlling at least twoof the finishing control parameters using a secondary friction sensorinformation combined with workpiece finishing sensor information is morepreferred. Using a electronic finishing sensor subsystem to control thefinishing control parameters is preferred. Feedback information selectedfrom the group consisting of finishing rate information and productquality information such as surface quality information is preferred.Non-limiting preferred examples of process rate information includepolishing rate, planarizing rate, and workpiece finished per unit time.Non-limiting preferred examples of quality information include firstpass first quality yields, focal plane deviation, total thicknessvariation, measures of non uniformity. Non-limiting examplesparticularly preferred for electronics parts include Total ThicknessVariation (TTV), Focal plane deviation (FPD), Within-WaferNon-Uniformity (WIW NU), and surface quality.

In situ process control systems relying on workpiece finishing sensorsare generally known to those skilled in the CMP industry. Commercial CMPequipment advertised by Applied Materials and IPEC reference some ofthis equipment.

Finishing element conditioning

A finishing element can be conditioned before use or between thefinishing of workpieces. Conditioning a finishing element is generallyknown in the CMP field and generally comprises changing the finishingelement finishing surface in a way to improve the finishing of theworkpiece. As an example of conditioning, a finishing element having nobasic ability or inadequate ability to absorb or transport a finishingcomposition can be modified with an abrasive finishing elementconditioner to have a new texture and/or surface topography to absorband transport the finishing composition. As a non-limiting preferredexample, an abrasive finishing element conditioner having a mechanicalmechanism to create a finishing element finishing surface which moreeffectively transports the finishing composition is preferred. Theabrasive finishing element conditioner having a mechanical mechanism tocreate a finishing element finishing surface which more effectivelyabsorbs the finishing composition is also preferred. A abrasivefinishing element conditioner having a mechanical mechanism comprising aplurality of abrasive points which through controlled abrasion canmodify the texture or surface topography of a finishing elementfinishing surface to improve finishing composition absorption and/ortransport is preferred. An abrasive finishing element conditioner havinga mechanical mechanism comprising a plurality of abrasive pointscomprising a plurality of diamonds which through controlled abrasion canmodify the texture and/or surface topography of a finishing elementfinishing surface to improve finishing composition absorption and/ortransport is preferred.

Modifying a virgin finishing element finishing surface with a finishingelement conditioner before use is generally preferred. Modifying afinishing element finishing surface with a finishing element conditionera plurality of times is also preferred. conditioning a virgin finishingelement finishing surface can improve early finishing performance of thefinishing element such as by exposing the lubricants. Modifying afinishing element finishing surface with a finishing element conditionera plurality of times during it useful life in order to improve thefinishing element finishing surface performance over the finishing cycletime by exposing new, unused lubricant, particularly new lubricantparticles, is preferred. Conditioning a finishing surface by cleaning ispreferred. Nondestruction conditioning is a preferred form ofconditioning. Conditioning a finishing element finishing surface aplurality of times during it useful life can keep the finishing elementfinishing surface performance higher over its useful lifetime byexposing fresh lubricant particles to improve finishing performance isalso preferred. Using feedback information, preferably informationderived from a friction sensor probes, to select when to modify thefinishing element finishing surface with the finishing elementconditioner is preferred. Using feedback information, preferablyinformation derived from a friction sensor probe, to optimize the methodof modifying the finishing element finishing surface with the finishingelement conditioner is more preferred. Use of feedback information isdiscussed further herein in other sections. When using a fixed abrasivefinishing element, a finishing element having three dimensionallydispersed lubricants is preferred because during the finishing elementconditioning process, material is often mechanically removed from thefinishing element finishing surface and preferably this removal exposesfresh lubricants, particularly lubricant particulates, to improvefinishing.

Nonlimiting examples of textures and topographies useful for improvingtransport and absorption of the finishing composition and/or finishingelement conditioners and general use are given in U.S. Pat. Nos.5,216,843 to Breivogel, 5,209,760 to Wiand, 5,489,233 to Cook et. al.,5,664,987 to Renteln, 5,655,951 to Meikle et. al., 5,665,201 to Sahota,and 5,782,675 to Southwick and are included herein by reference in theirentirety for general background and guidance and modification by thoseskilled in the art.

Cleaning composition

After finishing the workpiece such as a electronic wafer, the workpiecemust be carefully cleaned before the next manufacturing process step. Alubricant or abrasive particles remaining on the finished workpiece cancause quality problems later on and yield losses.

A lubricant which can be removed from the finished workpiece surface bysupplying a water composition to the finished workpiece is preferred anda lubricant which can be removed from the finished workpiece surface bya hot water composition to the finished workpiece is also preferred. Anexample of a water composition for cleaning is a water solutioncomprising water soluble surfactants. An effective amount of lubricantwhich lowers the surface tension of water to help clean abrasive andother adventitious material from the workpiece surface after finishingis particularly preferred.

A lubricant which can be removed from the finished workpiece surface ispreferred for many applications. A lubricant which can be removed fromthe finished workpiece surface by supplying deionized or pure water tothe finished workpiece to substantially remove all of the lubricant ispreferred and a lubricant which can be removed from the finishedworkpiece surface by supplying hot deionized or pure water to thefinished workpiece to substantially remove all of the lubricant is alsopreferred. A lubricant which can be removed from the finished workpiecesurface by supplying a deionized or pure water to the finished workpieceto completely remove the lubricant is more preferred and a lubricantwhich can be removed from the finished workpiece surface by supplyinghot deionized or pure water to the finished workpiece in to completelyremove the lubricant is also more preferred. Supplying a cleaningcomposition having a surfactant which removes lubricant from theworkpiece surface just polished is a preferred cleaning step. Alubricant which lowers the surface tension of the water and thus helpsremove any particles from the finished workpiece surface is preferred.

By using water to remove lubricant, the cleaning steps are lower costand generally less apt to contaminate other areas of the manufacturingsteps. A water cleaning based process is generally compatible with manyelectronic wafer cleaning process and thus is easier to implement on acommercial scale.

Cleaning composition

After finishing the workpiece such as a electronic wafer, the workpiecemust be carefully cleaned before the next manufacturing process step. Alubricating aid or abrasive particles remaining on the finishedworkpiece can cause quality problems later on and yield losses.

A finishing aid which can be removed from the finished workpiece surfaceby supplying a water composition to the finished workpiece is preferredand a finishing aid which can be removed from the finished workpiecesurface by supplying a hot water composition to the finished workpieceis also preferred. An example of a water composition for cleaning is awater solution comprising water soluble surfactants. An effective amountof lubricating aid which lowers the surface tension of water to helpclean abrasive and other adventitious material from the workpiecesurface after finishing is particularly preferred.

A lubricating aid which can be removed from the finished workpiecesurface by supplying pure water to the finished workpiece tosubstantially remove all of the lubricating aid is preferred and alubricating aid which can be removed from the finished workpiece surfaceby supplying hot pure water to the finished workpiece to substantiallyremove all of the lubricating aid is also preferred. A lubricating aidwhich can be removed from the finished workpiece surface by supplying apure water to the finished workpiece to completely remove thelubricating aid is more preferred and a lubricating aid which can beremoved from the finished workpiece surface by supplying hot pure waterto the finished workpiece in to completely remove the lubricating aid isalso more preferred. A preferred form of pure water is deionized water.Supplying a cleaning composition having a surfactant which removeslubricating aid from the workpiece surface just polished is a preferredcleaning step. A lubricating aid which lowers the surface tension of thewater and thus helps remove any particles from the finished workpiecesurface is preferred.

By using water to remove lubricating aid, the cleaning steps are lowercost and generally less apt to contaminate other areas of themanufacturing steps. A water cleaning based process is generallycompatible with many electronic wafer cleaning process and thus iseasier to implement on a commercial scale.

Further comments on method of operation

Some particularly preferred embodiments directed at the method offinishing are now discussed. The interface between the finishing surfacefinishing element and the workpiece being finished is referred to hereinas the operative finishing interface.

Providing an abrasive finishing surface for finishing is preferred andproviding an abrasive finishing element having a finishing surface forfinishing is more preferred and providing an fixed abrasive finishingsurface for finishing is even more preferred and providing an fixedabrasive finishing element having a finishing surface for finishing iseven more particularly preferred. Fixed abrasive finishing generallyproduces less abrasive to clean from the workpiece surface that wasfinished. Providing the workpiece surface being finished proximate tothe finishing surface is preferred and positioning the workpiece surfacebeing finished proximate to the finishing surface is more preferred.

Supplying an operative finishing motion between the workpiece surfacebeing finished and the finishing element finishing surface is preferredand applying an operative finishing motion between the workpiece surfacebeing finished and the finishing element finishing surface is morepreferred. The operative finishing motion creates the movement andpressure which supplies the finishing action such as chemical reactions,tribochemical reactions and/or abrasive wear. Applying an operativefinishing motion that transfers the finishing aid to the interfacebetween the finishing surface and the workpiece surface being finishedis preferred and applying an operative finishing motion that transfersthe finishing aid, forming a marginally effective lubricating layerbetween the finishing surface and the workpiece surface being finishedis more preferred and applying an operative finishing motion thattransfers the finishing aid, forming a marginally effective lubricatingboundary layer between the finishing surface and the workpiece surfacebeing finished is even more preferred. The lubrication at the interfacereduces the occurrence of high friction and related workpiece surfacedamage. Applying an operative finishing motion that transfers thefinishing aid, forming a lubricating boundary layer between at least aportion of the finishing surface and the semiconductor wafer surfacebeing finished is preferred and applying an operative finishing motionthat transfers the finishing aid, forming a marginally effectivelubricating layer between at least a portion of the finishing surfaceand the semiconductor wafer surface being finished so that abrasive wearoccurs to the semiconductor wafer surface being finished is morepreferred and applying an operative finishing motion that transfers thefinishing aid, forming a marginally effective lubricating boundary layerbetween at least a portion of the finishing surface and thesemiconductor wafer surface being finished so that tribochemical wearoccur to the semiconductor wafer surface being finished is even morepreferred and applying an operative finishing motion that transfers thefinishing aid, differentially lubricating different regions of theheterogeneous semiconductor wafer surface being finished even moreparticularly preferred. With heterogeneous workpiece surfaces, thepotential to differentially lubricate and finish a workpiece surface hashigh value where the differential lubrication is understood andcontrolled.

Changing the pressure at the operative finishing interface can changethe lubricating boundary layer performance. Changing the motion such asspeed or type of motion can change the lubricating boundary layerperformance. Changing the pressure applied in the operative finishinginterface, either total pressure or regional pressure can change thelubricating boundary layer performance. Changing the temperature in theoperative finishing interface, either average or regional temperaturescan change the lubricating boundary layer performance. Changing theconcentration of the boundary lubricant by changing finishing elementscan change the lubricating boundary performance. Changing the chemistryof the boundary lubricant in the finishing element can change thelubricating boundary performance by changing finishing elements duringthe finishing cycle time can be a lubricating control parameter. Theabove parameters comprise preferred lubricating boundary layer controlparameters and can be used to effect changes in the finishing of theworkpiece surface being finished. Changing a lubricating boundary layercontrol parameter to change the tangential force of friction at theoperative finishing interface is preferred and changing a lubricatingboundary layer control parameter to change the tangential force offriction at a region in the operative finishing interface is morepreferred and changing a lubricating boundary layer control parameter tochange the tangential force of friction in at least two regions of theoperative finishing interface is even more preferred. Changing a controlparameter to change the tangential force of friction at the operativefinishing interface is preferred and changing a control parameter tochange the tangential force of friction at a region in the operativefinishing interface is more preferred and changing a control parameterto change the tangential force of friction in at least two regions ofthe operative finishing interface is even more preferred. Changing thelubricating boundary control parameters at least once during thefinishing cycle time is preferred and changing the lubricating controlparameters at least twice during the finishing cycle time is morepreferred. Changing the lubricating boundary layer control parameters insitu is preferred and changing the lubricating boundary layer controlparameters in situ with a subsystem controller is more preferred andchanging the lubricating boundary layer control parameters in situ witha controller based on a secondary friction sensor signal is even morepreferred.

Changing at least one control parameter in situ is preferred andchanging at least one control parameter in situ with a subsystemcontroller is more preferred and changing at least one control parameterin situ with a controller based on a friction sensor signal is even morepreferred. Controlling at least one control parameter in situ ispreferred and controlling at least one control parameter in situ with asubsystem controller is more preferred and controlling at least onecontrol parameter in situ with a controller based on a friction sensorsignal is even more preferred. Changing at least one control parameterin situ is preferred and changing at least one control parameter in situwith a subsystem controller is more preferred and changing at least onecontrol parameter in situ with a controller based on a secondaryfriction sensor signal is preferred. Controlling at least one controlparameter in situ is preferred and controlling at least one controlparameter in situ with a subsystem controller is more preferred andcontrolling at least one control parameter in situ with a controllerbased on a secondary friction sensor signal is even more preferred.

Applying higher pressure in the unwanted raised region on thesemiconductor wafer surface compared to pressure applied to the regionbelow the unwanted raised region causing the boundary layer lubricationthickness to be less on the unwanted raised region and the boundarylubrication thickness to be greater on at least portion of thesemiconductor wafer surface below the raised region is a preferredmethod for differential finishing rates. Applying higher pressure in theunwanted raised region on the semiconductor wafer surface compared topressure applied to the region below the unwanted raised region causingthe boundary layer lubrication thickness to be less on the unwantedraised region and a higher temperature on the unwanted raised region andthe boundary lubrication thickness to be greater on at least portion ofthe semiconductor wafer surface below the raised region and a lowertemperature is more preferred method for differential finishing rates.

Applying an operative finishing motion in the operative finishinginterface forming an organic lubricating layer such that a tangentialfriction force is created in the operative finishing interface which isdependent on lubricant properties other than lubricant viscosity ispreferred. Applying an operative finishing motion in the operativefinishing interface forming an organic lubricating layer such that atangential friction force is created in the operative finishinginterface which depends on lubricant properties other than lubricantviscosity is preferred. Applying an operative finishing motion in theoperative finishing interface forming a differential organic lubricatinglayer such that a plurality of different tangential friction forces arecreated in different regions of the operative finishing interface andwherein the plurality of the different tangential friction forces aredependent on lubricant properties other than lubricant viscosity is morepreferred. Applying the greater tangential friction force in theunwanted raised region of the semiconductor wafer surface being finishedand also applying the lower tangential friction force to a region belowand proximate to the unwanted raised region of the semiconductor wafersurface being finished is also more preferred. By creating this type oflubricating layer, finishing of the semiconductor wafer can beaccomplished with good finishing rates and reduced unwanted surfacedefects. Planarization can be improved. Within die nonuniformity can beimproved.

A lubrication control parameter is a parameter which affects thelubrication of the operative finishing interface. A boundary lubricationcontrol parameter is a parameter which affects the boundary lubricationin the operative finishing interface. A parameter selected from thegroup consisting of the lubricant chemistry, lubricant concentration,lubricant transfer rate, operative finishing interface temperature,operative finishing interface pressure, and operative finishinginterface motion is a preferred group of lubricating boundary layercontrol parameters. A parameter selected from the group consisting ofthe local lubricant chemistry, local lubricant concentration, locallubricant feed rate, local operative finishing interface temperature,local operative finishing interface pressure, and local operativefinishing interface motion is a preferred group of local lubricatingboundary layer control parameters. A local operative finishing interfacepressure and local lubricating boundary layer is the local pressure andlubrication as illustrated and described in FIG. 5 and 6 herein.

Supplying an organic lubricant for a portion of finishing cycle time ispreferred. Supplying an organic lubricant for a secondary finishing stepafter a first finishing step free of lubricant can be preferred. Usingtwo finishing steps, one with lubricant and one free of lubricant canreduce unwanted surface damage when finishing a semiconductor wafer.Using two finishing steps can also increase the finishing rate.

A finishing aid selected from the group consisting of a lubricating aidand chemically reactive aid and both being free of an encapsulatingfilms is preferred. A finishing aid which reacts with the workpiecesurface being finished is preferred and which reacts with a portion ofthe workpiece surface being finished is more preferred and whichdifferentially reacts with heterogeneous portions of a workpiece surfacebeing finished is even more preferred. By reacting with the workpiecesurface, control of finishing rates can be improved and some surfacedefects minimized or eliminated. A finishing aid which reduces frictionduring finishing is also preferred because surface defects can beminimized.

Cleaning the workpiece surface reduces defects in the semiconductorlater on in wafer processing.

Supplying a finishing aid to the workpiece surface being finished whichchanges the rate of a chemical reaction is preferred. Supplying afinishing aid to the workpiece surface being finished having a propertyselected from the group consisting of workpiece surface coefficient offriction, workpiece finish rate change, a heterogeneous workpiecesurface having differential coefficient of friction, and a heterogeneousworkpiece surface having differential finishing rate change whichreduces unwanted damage to the workpiece surface is particularlypreferred.

Using the method of this invention to finish a workpiece, especially asemiconductor wafer, by controlling finishing for a period of time withan electronic control subsystem connected electrically to the finishingequipment control mechanism to adjust in situ at least one finishingcontrol parameter that affect finishing selected from the groupconsisting of the finishing rate and the finishing uniformity ispreferred. Finishing control parameters are selected from the groupconsisting of the finishing composition, finishing composition feedrate, finishing temperature, finishing pressure, operative finishingmotion velocity and type, and finishing element type and conditionchange are preferred. The electronic control subsystem is operativelyconnected electrically to the lubrication control mechanism. Themeasurement and control subsystem can be separate units and/orintegrated into one unit. A preferred method to measure finishing rateis to measure the change in the amount of material removed in angstromsper unit time in minutes (.ANG./min). Guidance on the measurement andcalculation for polishing rate for semiconductor part is found in U.S.Pat. No. 5,695,601 to Kodera et. al. issued in 1997 and is includedherein in its entirety for illustrative guidance.

An average finishing rate range is preferred, particularly forworkpieces requiring very high precision finishing such as in processelectronic wafers. Average cut rate is used as a preferred metric todescribe preferred finishing rates. Average cut rate is metric generallyknown to those skilled in the art. For electronic workpieces, such aswafers, a cut rate of from 100 to 25,000 Angstroms per minute on atleast a portion of the workpiece is preferred and a cut rate of from 200to 15,000 Angstroms per minute on at least a portion of the workpiece ismore preferred and a cut rate of from 500 to 10,000 Angstroms per minuteon at least a portion of the workpiece is even more preferred and a cutrate of from 500 to 7,000 Angstroms per minute on at least a portion ofthe workpiece is even more particularly preferred and a cut rate of from1,000 to 5,000 Angstroms per minute on at least a portion of theworkpiece is most preferred. A finishing rate of at least 100 Angstromsper minute for at least one of the regions on the surface of theworkpiece being finished is preferred and a finishing rate of at least200 Angstroms per minute for at least one of the materials on thesurface of the workpiece being finished is preferred and a finishingrate of at least 500 Angstroms per minute for at least one of theregions on the surface of the workpiece being finished is more preferredand a finishing rate of at least 1000 Angstroms per minute for at leastone of the regions on the surface of the workpiece being finished iseven more preferred where significant removal of a surface region isdesired. During finishing there are often regions where the operatordesires that the finishing stop when reached such when removing aconductive region (such as a metallic region) over a non conductiveregion (such as a silicon dioxide region). For regions where it isdesirable to stop finishing (such as the silicon dioxide region exampleabove), a finishing rate of at most 1000 Angstroms per minute for atleast one of the regions on the surface of the workpiece being finishedis preferred and a finishing rate of at least 500 Angstroms per minutefor at least one of the materials on the surface of the workpiece beingfinished is preferred and a finishing rate of at least 200 Angstroms perminute for at least one of the regions on the surface of the workpiecebeing finished is more preferred and a finishing rate of at least 100Angstroms per minute for at least one of the regions on the surface ofthe workpiece being finished is even more preferred where significantremoval of a surface region is desired. The finishing rate can becontrolled lubricants and with the process control parameters discussedherein.

Using finishing of this invention to remove raised surface perturbationsand/or surface imperfections on the workpiece surface being finished ispreferred. Using the method of this invention to finish a workpiece,especially a semiconductor wafer, at a planarizing rate and/orplanarizing uniformity according to a controllable set of operationalparameters that upon variation change the planarizing rate and/orplanarizing uniformity and wherein the operational parameters of atleast two operational parameters are selected from the group consistingof the type of lubricant, quantity of lubricant, and time periodlubrication is preferred. Using the method of this invention to polish aworkpiece, especially a semiconductor wafer, wherein an electroniccontrol subsystem connected electrically to an operative lubricationfeed mechanism adjusts in situ the subset of operational parameters thataffect the planarizing rate and/or the planarizing uniformity andwherein the operational parameters are selected from the groupconsisting of the type of lubricant, quantity of lubricant, and timeperiod lubrication is preferred. The electronic control subsystem isoperatively connected electrically to the operative lubrication feedmechanism.

Using the method of this invention to polish or planarize a workpiece,especially a semiconductor wafer, supplying lubrication moderated by afinishing element having at least two layers is preferred. Morepreferably the finishing element having at least two layers has afinishing surface layer which has a higher hardness than the subsurfacelayer. A finishing element having at least two layers has a finishingsurface layer which has a lower hardness than the subsurface layer ispreferred, particularly for polishing.

Finishing of a semiconductor wafer surface being finished a fixedabrasive finishing element having a finishing element surface layerhaving a lubricating aid therein and a fixed abrasive finishing surfacefurther the fixed abrasive finishing element further having a finishingelement subsurface layer free of lubricating aid therein a preferredfinishing element. A fixed abrasive finishing element having a finishingelement surface layer having a finishing surface, a dispersedlubricating aid, and fixed abrasive elements and the fixed abrasivefinishing element further comprising a finishing element subsurfacelayer free of lubricating aid is more preferred. This can reduce costsin the manufacture of the finishing element by reducing the costs ofincorporating the finishing aids such as lubricant throughout the entirethickness. Finishing with a finishing element wherein the finishingelement has a uniform dispersed lubricants beyond the useful finishingelement finishing surface thick used for finishing is preferred becausethen lubrication will be stable within a finishing cycle run and fromrun to run in during finishing of the expensive semiconductor wafersthus helping to reduce yield loss.

Summary

Illustrative nonlimiting examples useful technology have referenced bytheir patents numbers and all of these patents are included herein byreference in their entirety for further general guidance andmodification by those skilled in the arts. The scope of the inventionshould be determined by the appended claims and their legal equivalents,rather than by the preferred embodiments and details is discussedherein.

I claim:
 1. A method of finishing of a semiconductor wafer surface beingfinished comprising the steps of: providing a finishing element having afixed abrasive finishing surface and having an organic boundarylubricant therein which is free of encapsulating films; positioning thesemiconductor wafer surface being finished proximate to the finishingsurface; applying an operative finishing motion in an operativefinishing interface comprising the interface between the fixed abrasivefinishing surface and the semiconductor wafer surface being finished;and wherein applying the operative finishing motion transfers theorganic boundary lubricant from the finishing surface to the operativefinishing interface in a manner that forms an organic lubricatingboundary layer of from 1 to 6 molecules thick.
 2. A method of finishingof the semiconductor wafer surface being finished according to claim 1wherein the organic boundary lubricating layer comprises an organicsynthetic material.
 3. A method of finishing of the semiconductor wafersurface being finished according to claim 1 further comprising anadditional step of controlling the thickness of the organic lubricatingboundary layer by changing at least one process control parameter insitu based on feedback information from a control subsystem.
 4. A methodof finishing of the semiconductor wafer surface being finished accordingto claim 1 wherein applying the operative finishing motion transfers theorganic lubricant, forming a marginally effective organic lubricatingboundary layer in the operative finishing interface so that abrasivewear occurs to the semiconductor wafer surface being finished.
 5. Amethod of finishing of the semiconductor wafer surface being finishedaccording to claim 1 wherein applying the operative finishing motioncomprises transferring an organic lubricating boundary layer in theoperative finishing interface, reducing the wear on the exposed fixedabrasive finishing surface during finishing.
 6. A method of finishing ofa heterogeneous semiconductor wafer surface being finished comprisingthe steps of: providing a finishing element having a fixed abrasivefinishing surface and having a dispersed organic boundary lubricant, theorganic boundary lubricant being free of encapsulating films;positioning the semiconductor wafer surface being finished proximate tothe finishing surface; applying an operative finishing motion in anoperative finishing interface comprising the interface between the fixedabrasive finishing surface and the semiconductor wafer surface beingfinished; and wherein applying the operative finishing motion transfersthe organic boundary lubricant from the finishing surface to theoperative finishing interface forming an organic lubricating boundarylayer of from 1 to 6 molecules thick.
 7. A method of finishing of thesemiconductor wafer surface being finished according to claim 6 whereinapplying the operative finishing motion comprises the transferring of aneffective amount of organic lubricating boundary layer, reducing theformation of unwanted surface defects on the semiconductor wafer surfacebeing finished.
 8. A method of finishing of the heterogeneoussemiconductor wafer surface being finished according to claim 6 whereinthe heterogeneous semiconductor surface has at least one unwanted raisedregion wherein the organic lubricating boundary layer thickness is lesson the unwanted raised region and the organic lubricating boundary layerthickness is greater on at least a portion of the semiconductor surfacebelow and proximate to the unwanted raised region.
 9. A method offinishing of the heterogeneous semiconductor wafer surface beingfinished according to claim 6 wherein the heterogeneous semiconductorwafer surface has at least one unwanted raised region wherein theorganic lubricating boundary layer thickness on the unwanted raisedregion is at most one half the molecular layer thickness of the organiclubricating boundary layer thickness below and proximate to the unwantedraised region.
 10. A method of finishing of the heterogeneoussemiconductor wafer surface being finished according to claim 6 whereinthe heterogeneous semiconductor wafer surface has at least one unwantedraised region wherein the organic lubricating boundary layer thicknessis at most one third the molecular layer thickness of the organiclubricating boundary layer thickness below and proximate to the unwantedraised region.
 11. A method of finishing of the heterogeneoussemiconductor wafer surface being finished according to claim 6 whereinthe heterogeneous semiconductor wafer surface has at least a firstregion wherein the organic lubricating boundary layer thickness is atmost one third the molecular layer thickness compared to the organiclubricating boundary layer thickness on a second, different region. 12.A method of finishing of the heterogeneous semiconductor wafer surfacebeing finished according to claim 6 further comprising an additionalstep of controlling the thickness of the organic lubricating boundarylayer by changing at least one lubrication control parameter in a mannerthat changes the tangential force of friction in at least two differentregions of the operative finishing interface in response to an in situcontrol signal.
 13. A method of finishing of the semiconductor wafersurface being finished according to claim 12 wherein applying theoperative finishing motion comprises transferring and controlling theorganic lubricating boundary layer in the operative finishing interface,reducing the wear on the exposed fixed abrasive finishing surface duringfinishing.
 14. A method of finishing of the heterogeneous semiconductorwafer surface being finished according to claim 6 further comprising anadditional step of controlling the thickness of the organic lubricatingboundary layer by changing at least one control parameter in a mannerthat changes the tangential force of friction in at least two differentregions of the operative finishing interface in response to an in situcontrol signal.
 15. A method of finishing of a heterogeneoussemiconductor wafer surface being finished according to claim 6 furthercomprising an additional step of controlling the thickness of theorganic lubricating boundary layer by changing the lubrication controlparameters in situ based on feed back information from a controlsubsystem having an energy change sensor.
 16. A method of finishing ofthe semiconductor wafer surface being finished according to claim 15wherein applying the operative finishing motion comprises transferringand controlling the organic lubricating boundary layer in the operativefinishing interface, reducing the wear on the exposed fixed abrasivefinishing surface during finishing.
 17. A method of finishing of aheterogeneous semiconductor wafer surface being finished comprising thesteps of: providing a fixed abrasive finishing surface having aplurality of discrete, unconnected organic boundary lubricant regionsfree of encapsulating film; positioning the semiconductor wafer surfacebeing finished proximate to the finishing surface; applying theoperative finishing motion which transfers the organic boundarylubricant from the finishing surface to an operative finishing interfacecomprising the interface between the fixed abrasive finishing surfaceand the semiconductor wafer surface being finished forming adifferential organic lubricating boundary layer in the operativefinishing interface; and controlling the lubricating boundary layer filmphysical form by changing the lubrication control parameters in situbased on feed back information from a control subsystem having anoperative sensor.
 18. A method of finishing of the heterogeneoussemiconductor wafer surface being finished according to claim 17wherein: the heterogeneous semiconductor wafer surface has unwantedraised surface regions; and the finishing element finishing surfacecomprises a composition having a synthetic resin with a flexural modulusof at least 20,000 psi when measured by ASTM 790 B at 73 degreesFahrenheit; and a further step of increasing temperature on the unwantedraised region on the semiconductor wafer surface compared to thetemperature on the region below the unwanted raised region forming thelubricating boundary layer liquid film on the unwanted raised region andthe lubricating boundary layer solid film on at least a portion of thesemiconductor wafer surface below the raised region.
 19. A method offinishing of the heterogeneous semiconductor wafer surface beingfinished according to claim 18 wherein the unwanted raised region has ahigher finishing rate measured in angstroms per minute and the regionproximate to and below the unwanted raised region has lower finishingrate.
 20. A method of finishing of the heterogeneous semiconductor wafersurface being finished according to claim 17 wherein the unwanted raisedregion has a higher finishing rate measured in angstroms per minute andthe region proximate to and below the unwanted region has a lowerfinishing rate.
 21. A method of finishing of a heterogeneoussemiconductor wafer surface being finished comprising the steps of:providing a finishing element having an abrasive finishing surface andhaving an organic boundary lubricant therein; positioning thesemiconductor wafer surface being finished proximate to the finishingsurface; applying an operative finishing motion in an operativefinishing interface comprising the interface between the fixed abrasivefinishing surface and the semiconductor wafer surface being finished;and wherein applying the operative finishing motion transfers theorganic boundary lubricant from the finishing surface to the operativefinishing interface forming a heterogeneous organic lubricating boundarylayer of from 1 to 6 molecules thick on the semiconductor wafer surfacewherein: the operative finishing motion forms a friction in theinterface between a uniform region on the semiconductor wafer surfaceand the finishing element finishing surface; the organic lubricatingboundary layer physically or chemically interacts with and adheres tothe semiconductor wafer surface; and the friction formed between theuniform region on the semiconductor wafer surface and the finishingelement finishing surface is determined by lubricant properties otherthan viscosity.
 22. A method of finishing of the heterogeneoussemiconductor wafer surface being finished according to claim 21 whereinthe heterogeneous semiconductor surface has at least one unwanted raisedregion wherein the organic lubricating boundary layer thickness is atmost one half the molecular layer thickness of the lubricating boundarylayer thickness proximate to the unwanted raised region.
 23. A method offinishing of the heterogeneous semiconductor wafer surface beingfinished according to claim 22 further comprising an additional step ofcontrolling the thickness of the organic lubricating boundary layer bychanging at least one control parameter in a manner that changes thetangential force of friction in at least two different regions of theoperative finishing interface in response to an in situ control signal.24. A method of finishing of the heterogeneous semiconductor wafersurface being finished according to claim 21 wherein the heterogeneoussemiconductor wafer surface has at least one unwanted raised regionwherein the organic lubricating boundary layer thickness is at most onequarter the molecular layer thickness of the lubricating boundary layerthickness proximate to the unwanted raised region.
 25. A method offinishing of the heterogeneous semiconductor wafer surface beingfinished according to claim 24 further comprising an additional step ofcontrolling the thickness of the organic lubricating boundary layer bychanging at least one process control parameter in situ based on feedback information from a control subsystem.
 26. A method of finishing ofthe heterogeneous semiconductor wafer surface being finished accordingto claim 21 wherein the heterogeneous semiconductor wafer surface has atleast one unwanted raised region wherein the unwanted raised region hasa finishing rate measured in angstroms per minute of at least 1.6 timesfaster than in the proximate low local region measured in angstroms perminute.
 27. A method of finishing of the heterogeneous semiconductorwafer surface being finished according to claim 26 further comprising anadditional step of controlling the thickness of the organic lubricatingboundary layer by changing at least one control parameter in a mannerthat changes the tangential force of friction in at least two differentregions of the operative finishing interface in response to an in situcontrol signal.
 28. A method of finishing of the heterogeneoussemiconductor wafer surface being finished according to claim 21 whereinthe heterogeneous semiconductor wafer surface has at least one unwantedraised region wherein the unwanted raised regions have a finishing ratemeasured in angstroms per minute of from 2 to 300 times faster than inthe proximate low local region.
 29. A method of finishing of theheterogeneous semiconductor wafer surface being finished according toclaim 28 further comprising an additional step of controlling thethickness of the organic lubricating boundary layer by changing at leastone process control parameter in situ based on feedback information froma control subsystem.
 30. A method of finishing of a semiconductor wafersurface having a conductive region being finished comprising the stepsof: providing an abrasive finishing element finishing surface; providingan organic boundary lubricant between the finishing element finishingsurface and the conductive region of the semiconductor wafer surfacebeing finished; and applying an operative finishing motion between thesemiconductor wafer surface being finished and the finishing elementfinishing surface forming a heterogeneous organic lubricating boundarylayer of from 1 to 6 molecules thick on the conductive region of thesemiconductor wafer surface wherein: the operative finishing motionforms a friction in the interface between the conductive region on thesemiconductor wafer surface and the finishing element finishing surface;the organic lubricating boundary layer physically or chemicallyinteracts with and adheres to the conductive region on the semiconductorwafer surface; and the friction formed between the conductive region onthe semiconductor wafer surface and the finishing element finishingsurface is determined by lubricant properties other than viscosity. 31.A method of finishing of the heterogeneous semiconductor wafer surfacebeing finished according to claim 30 wherein the conductive region ofthe heterogeneous semiconductor surface has at least one unwanted raisedregion wherein the lubricating boundary layer thickness is at most onehalf the molecular layer thickness of the lubricating boundary layerthickness proximate to the unwanted raised region.
 32. A method offinishing of the heterogeneous semiconductor wafer surface beingfinished according to claim 30 wherein the heterogeneous semiconductorwafer surface has at least one unwanted raised region wherein theunwanted raised regions have a finishing rate measured in angstroms perminute of from 2 to 300 times faster than in the proximate low localregion.
 33. A method of finishing of the heterogeneous semiconductorwafer surface being finished according to claim 32 further comprising anadditional step of controlling the thickness of the organic lubricatingboundary layer by changing at least one control parameter in a mannerthat changes the tangential force of friction in at least two differentregions of the operative finishing interface in response to an in situcontrol signal.
 34. A method of finishing of a heterogeneoussemiconductor wafer surface having uwanted raised regions being finishedcomprising the steps of: providing an abrasive finishing surface havinga plurality of discrete, unconnected organic boundary lubricant regionsfree of encapsulating film; positioning the semiconductor wafer surfacebeing finished proximate to the finishing surface; applying theoperative finishing motion that transfers the organic boundary lubricantfrom the finishing surface to an operative finishing interfacecomprising the interface between the fixed abrasive finishing surfaceand the semiconductor wafer surface being finished forming adifferential organic lubricating boundary layer in the operativefinishing interface; and controlling the thickness of the organiclubricating boundary layer by changing at least one control parameter ina manner that changes the tangential force of friction in at least twodifferent regions of the operative finishing interface in response to anin situ control signal.
 35. A method of finishing of the heterogeneoussemiconductor wafer surface having uwanted raised regions being finishedaccording to claim 34 wherein: the region being finished comprises aconductive region; the conductive region of the heterogeneoussemiconductor surface has at least one unwanted raised region whereinthe lubricating boundary layer thickness is at most one half themolecular layer thickness of the lubricating boundary layer thicknessproximate to the unwanted raised region; and the conductive region hasat least one unwanted raised region's finishing rate measured inangstroms per minute of at least 2 times faster than the rate in theproximate low local region measured in angstroms per minute.
 36. Amethod of finishing of the heterogeneous semiconductor wafer surfacebeing finished according to claim 35 wherein the heterogeneoussemiconductor wafer surface has a diameter of at least 300 mm.
 37. Amethod of finishing of the heterogeneous semiconductor wafer surfacehaving uwanted raised regions being finished according to claim 34wherein: the region being finished comprises a polymeric region; thepolymeric region of the heterogeneous semiconductor surface has at leastone unwanted raised region wherein the lubricating boundary layerthickness is at most one half the molecular layer thickness of thelubricating boundary layer thickness proximate to the unwanted raisedregion; and the polymeric region has at least one unwanted raisedregion's finishing rate measured in angstroms per minute of at least 2times faster than the rate in the proximate low local region measured inangstroms per minute.
 38. A method of finishing of the heterogeneoussemiconductor wafer surface being finished according to claim 37 whereinthe heterogeneous semiconductor wafer surface has a diameter of at least300 mm.